From the Super Mario Wiki
“Run! Run for it!”
Shy Guys (Japanese: ヘイホー, Heihō) are timid troublemakers and common enemies in the Mario and Yoshi series. They are famous for the masks they wear. Yume Kōjō: Doki Doki Panic, a non-Mario game, was the game they debuted in; they were later carried over to the Mario universe when Super Mario Bros. 2 was created. Shy Guys usually work for Bowser and the Koopa Troop, but they originally worked for the evil king Wart.
Super Mario Bros. 2
Shy Guys make their first Mario game appearance in Super Mario Bros. 2, although the Shy Guys' real first appearance is in Yume Kōjō: Doki Doki Panic. In this game, Shy Guys, with the other 8 bits help Wart conquer the Subcon. They attack Mario, Luigi, Princess Toadstool, and Toad by walking in their general direction. They can be easily disposed by being picked up and thrown against another enemy or into a nearby abyss. They can also be defeated by having an object thrown at them.
Red Shy Guys walk off ledges while pink ones don't, striking a resemblance to Green and Red Koopa Troopas respectively, although the primary difference is that Red Shy Guys are known to turn in the direction of the player after landing. Red ones are also known to ride Autobombs and Ostros and often appear out of Vases. Pink ones became blue in the remakes of Super Mario Bros. 2. The Super Mario Advance remake introduces Giant Shy Guys. It takes time to pick them up because of their size. If the player picks up a Giant Shy Guy and throws it, hitting the ground or hitting another enemy with it, it will drop a heart.
The Super Mario Bros. Super Show!
In The Super Mario Bros. Super Show!, Shy Guys made uncommon appearances as antagonists, working for King Koopa. Like most other minions of King Koopa, Shy Guys would wear costumes to go with the theme of each episode.
Nintendo Comics System
Shy Guys appeared commonly in issues of Nintendo Comics System, where they were depicted as somewhat disgruntled soldiers of Bowser. Along with Koopa Troopas, they appeared to be the most common minions.
Nintendo Adventure Books
In Leaping Lizards, some Shy Guys are spotted among the crowds attending the International Mushroom Games. Upon entering a chamber in a cave in Koopa Capers, Luigi wonders why he is suddenly "shivering like a Shy Guy" before realizing how unusually cold the room is.
In Pipe Down!, Mario and Luigi can encounter a Shy Guy hopping through the Koopahari Desert, leaving footprints in the sand that look like the indentations left by the basketball Princess Toadstool was dribbling when she disappeared. In an elevator in the Mushroom Palace, if a lever with a mushroom printed on it is pulled, some Shy Guys, Tweeters and Cheep-Cheeps will swarm Mario and Luigi, leading to a Game Over.
In Dinosaur Dilemma, Mario and Yoshi can encounter some Shy Guys, but evade the enemies by just hopping over them. In Unjust Desserts, some Shy Guys are among the enemies Bowser has Magikoopa shrink and send after the shrunken Mario, who had made himself tiny in order to enter Yoshi's body and rescue the eaten Luigi.
In Brain Drain, a group of Shy Guys will ambush Luigi if he decides to follow Princess Toadstool after arriving at Dinosaur Island. Luigi can also spot some Shy Guys holding up the lunch line (due to their mumbling) in Iggy Koopa's lair, and in the WMUSH radio station after Iggy takes it over.
Super Mario World 2: Yoshi's Island / Super Mario Advance 3
Shy Guys' first chronological and true Mario appearance is in Super Mario World 2: Yoshi's Island and its remake Yoshi's Island: Super Mario Advance 3, where their name is hyphenated. Here they are extremely common and weak enemies, simply walking forward and occasionally stopping to look left and right. They sometimes appear out of Pipes unless Yoshi has a full six eggs. The colors they come in are red, yellow, green, and magenta and have different colored mask straps. Boo Guys, as well as other variants, also first appear in this game. Like other enemies, they can be defeated by jumping on them, unlike in SMB2, and can be eaten and turned into an egg. In dark levels of the game it is revealed that their shoes glow in the dark.
Shy Guys appear to be allies with Raphael the Raven in Tetris Attack. A spell was cast on all of them to work for Bowser. They appear in the 8th level, and are saved by Yoshi. It is unknown what happened to these brave Shy Guys after the events of the game. It's unknown if these Shy Guys actually serve anyone or are free Shy Guys.
In Yoshi's Story, Shy Guys are once again common enemies, walking forward and backward. Woozy Guys from Super Mario World 2: Yoshi's Island had disappeared, although more varieties rise up. Some Shy Guys carry Fruit or hide in trees. To defeat the Shy Guys that are in trees, Yoshi must Ground Pound near the tree they are hiding in, causing them to fall out. Additionally, if Yoshi Ground Pounds near a Shy Guy, its color will change, although the reason for this change is unknown. If Yoshi ground pounds near a Shy Guy while under the effects of a Heart Fruit, the Shy Guy will turn into a lucky fruit.
If Yoshis eat a Shy Guy with the same color, they will be awarded with three petals on their Smile Meter instead of one. Additionally, when a Baby Yoshi eats a Shy Guy, the Yoshi Egg that is produced will be the same color as the Shy Guy. This game also introduces the first "good" Shy Guy, the White Shy Guy. Shy Guys have voices in this game and can be distinctly heard saying "Hei-Ho" (their Japanese name) and other sounds.
Yoshi Touch & Go
Shy Guys reappear in Yoshi Touch & Go. They are vulnerable to all attacks and are worth a Yellow Coin. In this game, like all the other enemies, bumping into a Shy guy causes an instant Game Over. Shy Guy serves the same purpose in this game as in the previous, as working as a common soldier for Baby Bowser. Many varieties of Shy Guy appear on the island, red being the most common. Balloon Shy Guys were introduced in this game as a sub-species.
Yoshi's Island DS
Shy Guys also appear in Yoshi's Island DS, once again, as very common and weak enemies. Yoshi can use any tactic to defeat them: jumping, egg-throwing, or swallowing. While Shy Guys in this game play virtually the same role as they did in Yoshi's Island, there is a boss known as Big Guy the Stilted, a massive robot seemingly built by Shy Guys.
Other than being common enemies, Shy Guys also have their own section in the Island Museum. Yoshi can view the different types of Shy Guys in that section, though Shy Guys that do not wander on land, such as Tube Guys, are only in the marine section.
All of the colors from the original Super Mario World 2: Yoshi's Island, including blue and excluding magenta, appear in this game.
Yoshi's New Island
Shy Guys appear as enemies in Yoshi's New Island, where they simply walk around, like in the past games. Mega Shy Guys appear, turning into Mega Eggdozers if swallowed by a Yoshi. A new species, Metal Shy Guy, appears and turn into a Metal Eggdozer instead if a Yoshi swallows it.
Shy Guys are set to appear in the upcoming game Yarn Yoshi. They seem to have a yarn-like appearance, similar to Yoshi. Shy Guys just keep walking while Yoshi is in his thread form. Once he gets his amigurumi crochet form, they run away from him.
Super Mario Adventures
Super Mario RPG: Legend of the Seven Stars
“Hold still, okay?!”
In Super Mario RPG: Legend of the Seven Stars, Shy Guys riding pogo sticks, under the name Shysters, work for the Smithy Gang. They helped Mack to invade the Mushroom Kingdom and the castle. Stronger versions of Shysters named Shypers and Springers are also found in the alternate dimension of Smithy's Factory.
More traditional Shy Guys also appear throughout the world of the game, at places such as the Rose Way, where they sit on top of Treasure Boxes, manned Boards, or fought alongside Lakitus that lower them towards Mario and Mallow with a fishing pole. Sling Shys, stronger versions of the traditional Shy Guys, also work for Valentina in Nimbus Land. The rare Shy Rangers also often lurk the undergrounds of Pipe Vault.
Mario Party series
Shy Guys appear in the Mario Party series mainly in minigames. In this series, Shy Guys are friends of the Mario cast.
Mario Party / Mario Party 2
Mario Party 4
In Mario Party 4 a Shy Guy (with Toad, a Boo, a Goomba and a Koopa Troopa) find the mystical Party Cube, with which they can create parties and game boards. In this game Shy Guy wears a fedora, much like Indiana Jones, and is hosting his own board, Shy Guy's Jungle Jam. He created the board because he wants to go an an adventure, but isn't brave enough to go on his own. Whenever he talks, he appears to be nervous and meek. Shy Guy also appears as a playable character in Beach Volley Folley.
Mario Party Advance
A single, friendly, Shy Guy appears as the conductor of Shroom City's Train Station in Mario Party Advance. One of the games quests involves retrieving a ticket from him and delivering it to Goomba (an easy feat, since the Train Station is located only a few spaces away from the Goomba House). In another of the game's quests, the Shy Guy asks the Player to obtain Coal for him, because the train's supply has apparently run out. The Player can find the Coal in the Vending Machines. Once this is done, he will reward the player with the Gaddget, Cake Maker. The ending of the game says that he is starting to run low on coal again.
Mario Party 7
Multiple Shy Guys appear in Mario Party 7, though they appear as Singing Shy Guys on the Grand Canal board and as Top Hat Shy Guys on the Neon Heights board. They also appear in the background of some minigames, jumping and cheering for the players.
Mario Party 8
Shy Guys also get their own board in Mario Party 8, titled Shy Guy's Perplex Express, the goal for the players is to give 20 Coins to the Shy Guy Conductor. If the player lands on a Happening space on the top of the train, Shy Guy Conductor will ask the player to help Holly Koopa find her candy that was stolen. At least one Shy Guy appears in the following minigames: Picture Perfect, Swing Kings, Water Ski Spree, Cardiators, Crops 'n' Robbers, Settle It in Court, Fruit Picker, Pour to Score, and Stampede. There is also an Extra minigame similar to Shy Guy Says from the first two Mario Party games called Flagging Rights.
Mario Party DS
Shy Guys are featured in many of the minigames in Mario Party DS, such as Fast Food Frenzy, Rotisserie Rampage and Sweet Sleuth. Shy Guys also have their own character figure and badge entitled "Shy Guy Rival".
Mario Party 9
Shy Guy appears as an unlockable playable character in Mario Party 9. Along with Magikoopa, Shy Guy competes against the player in Solo mode, and if one of them wins a board the player must try again. Shy Guy and Magikoopa are both unlocked by completing Solo mode once, after which they can be played in any game mode except Solo.
Mario Party: Island Tour
Shy Guys appear in Mario Party: Island Tour for the Nintendo 3DS. They have a board, Shy Guy's Shuffle City, where they appear on the sidelines. Their masks also appear on some cards of various colours. One Shy Guy also appears as a judge in the minigame The Choicest Voice. Other than that, many Shy Guys appear in the background of various minigames.
Mario Golf series
While Shy Guys themselves don't appear in the game Mario Golf (they appear in artwork for the game), they are clearly referenced in the game by one of the courses, Shy Guy Desert. In addition to that, each time a player completes a hole, a silhouette of a Shy Guy is briefly shown.
Mario Golf (Game Boy Color)
Paper Mario series
“Oh no... Poor me...”
Shy Guys, as well as several variations of them, are semi-common enemies in Paper Mario. After Mario returns from Forever Forest, he finds Toad Town overrun by Shy Guys. He can hit the enemies with his Hammer to make them run out of town. Once Mario discovers Shy Guy's Toy Box, the secret hide-out of the Shy Guys, they can be fought as normal enemies. They have two main attacks: They can simply tackle Mario for 2 damage, or they can do an acrobatic attack, dealing 3 points of damage and bowing to an unseen but not unheard crowd.
It is revealed that Shy Guys have their own language called Shy Guy that only Russ T. can understand.
During the ending cinema of the game some Shy Guys can be seen talking with Watt, a baby Li'l Sparky. They can also be seen on General Guy's parade float, dancing. Also, the Shy Guys' parade float in the ending have "Heihos" ("Heiho" being Shy Guy's Japanese name) written on both the left and right of General Guy.
Paper Mario: The Thousand-Year Door
Although Shy Guys were not actual enemies in Paper Mario: The Thousand-Year Door, they do appear in the Audience of most of the battles, and a few statues of Shy Guys also appear on the Poshley Heights fountain. Occasionally, if part of the audience, Shy Guys will run onto the backstage and cause pieces of the set to fall on Mario or his enemies. This is also used to signal the first occurrence of a stage hazard (like fog, ice, fire, etc.). Shy Guys will give Mario Star Power along with the other audience members when he performs a move correctly. The name Heihoo, which is Japanese for "Shy Guy," appears alongside other scrapped enemy names (among which are also Faia Heihoo "Fire Shy Guy", Komando Heihoo "Commando Shy Guy", and Burakku Heihoo "Black Shy Guy") in Paper Mario: The Thousand-Year Door's coding, suggesting that Shy Guys were once going to appear as enemies in that game.
The X-Nauts somewhat take a role of Shy Guys, as their commander, Lord Crump, gets inside a machine that slightly resembles General Guy's tank (except with arms and legs). In addition, when the X-Nauts are running away from the Great Tree, one of them falls over, mirroring the straggler Shy Guy in the Shy Squad in the first Paper Mario. Additionally, X-Nauts make formations similar to the Shy Squad and others when attacking Mario during the ship battle between Crump and Cortez, and they are fought before Crump himself is faced.
Super Paper Mario
Shy Guys solely appear in the audience of Super Paper Mario when a Stylish Move is performed. Sprites for them are also among the unused data in the game. They, along with Wigglers, Fly Guys, Spear Guys, Stilt Guys, and Monty Moles, were removed for unknown reasons during the game's production.
Paper Mario: Sticker Star
In Paper Mario: Sticker Star, Shy Guys appear, having their Super Paper Mario appearance, though their feet are more within their robes. They only appear in World 3 and World 4. In battle, a Shy Guy's only attack is running up to Mario and flailing its arms at him. Sometimes, the Shy Guy might trip before reaching Mario, cancelling the attacks. Along with standard Shy Guys, a new sub-species known as Mariachi Guys appear. There are also Shy Guys holding paper clips, known as Clip Guys and Paint Guys who holds a bucket of paint. Both of these enemies can assist a Shy Guy in battle. Additionally, Spear Guys and Snifits also appear in the game. Additionally, there are 2 Shy Guys in World 4-6 which are harrassing the Travelling Toad. They are very powerful, similar to Anti Guys, each having 120 HP and an attack power of 7. When defeated, they drop a Secret Door sticker.
Mario Tennis series
A Shy Guy is an unlockable character in Mario Tennis for the Nintendo 64 (where he is unlocked after the Star Cup is won in Singles). This is Shy Guy's first playable appearance. It is a Technique character, and during its trophy ceremony it turns into a Fly Guy and starts flying around. Shy Guy comes back for another round of tennis in Mario Power Tennis, but this time it is available from the start. Once again, it is a Technique character. For its Offensive Power Shot, it turns into a Spear Guy and electrifies the ball. For its Defensive Power Shot, it turns into a Spear Guy, but this time it extends its spear to hit the ball. When it wins a Singles Tournament, a cutscene plays. During this, it walks up to the podium where the trophy is while Luigi is there applauding it. Accidentally, Shy Guy trips over a step on the small staircase and its mask falls off. The screen doesn't show what it looks like without its mask but an astonished Luigi sees it and just stands there with his mouth hanging wide open. Shy Guy quickly puts its mask back on, takes the trophy and walks off of the podium, thus ending the cutscene. This implies that Shy Guys probably wear masks because they are hiding something very scary or disturbing, or it might be because of their extreme shyness, hence their name.
Super Smash Bros. series
Super Smash Bros. Melee
Shy Guys also appear in the Yoshi's Story stage of Super Smash Bros. Melee. Although they are actually Fly Guys, they are called Shy Guys. The Fly Guys will fly past the stage. They are unable to damage players, but they carry Food with them, which can be dropped on the ground if they are attacked. If the player KOs a Shy Guy, they receive the bonus "Shy Guy KO". They also have a trophy in their honor.
Super Smash Bros. Brawl
Shy Guys appear in the Mario Circuit stage, racing in go-karts in the game Super Smash Bros. Brawl. They are the only racers, and they will appear going across the top or bottom of the stage. If hit, the Shy Guy racers will spin out of control and wipe out, but come back shortly afterwards. It is possible to get rid of every Shy Guy on the track. If this happens no more Shy Guys will appear. They also have a trophy and sticker too. Fly Guys also appear on the Yoshi's Island stage.
Super Smash Bros. for Nintendo 3DS
Shy Guys will appear in the Rainbow Road stage in Super Smash Bros. for Nintendo 3DS as obstacles like in Super Smash Bros. Brawl. This time, the karts they drive take their appearance from Mario Kart 7.
Shy Guys are also to appear in the Nintendo 3DS version as enemies in the Smash Run mode.
Mario Kart series
Mario Kart: Super Circuit
In Mario Kart: Super Circuit, there is a course called Shy Guy Beach. As the racers race around the circular chain of islands, a pirate ship manned by Pirate Guys can be seen in the background. It shoots cannonballs at the racers to hinder them.
Mario Kart: Double Dash!!
In Mario Kart: Double Dash!!, Shy Guys appear ice-skating in Sherbet Land, acting as obstacles for the racers. A statue of two Shy Guys can be seen in the background of Baby Park, and they appear in the audience of Waluigi Stadium.
Mario Kart DS
A Shy Guy is playable in the download play version of Mario Kart DS, with colors such as white, black, green, light blue, dark blue, red, yellow or pink. Shy Guy's standard kart, which has the same stats as Yoshi's Standard YS, excels in acceleration and handling.
Mario Kart Wii
In Mario Kart Wii, Shy Guys appear as spectators and stage hazards on various tracks. In the city section of Moonview Highway, the Shy Guy emblem can be seen on the guard rails. Also, Shy Guys appear on DK Summit as a snowboarder and track hazard doing tricks in the half pipe. If a player hits one of the different-colored Shy Guys, the player will spin out and slow down. The Shy Guy will not stop, however. GBA Shy Guy Beach returns as a retro course.
Mario Kart 7
Shy Guy appears a playable character in the Nintendo 3DS game, Mario Kart 7. Unlike in Mario Kart DS, it can be used without using download play, but it can also be played through download play if other players do not have Mario Kart 7. However, players who use download play will only be restricted to the standard parts, but the Shy Guys will come in different colors as a result.
He can be unlocked by getting a gold trophy in the 150cc Shell Cup. He is a Feather class racer, with acceleration and Off-road being its best stats. There is one course that belongs to Shy Guy in the game, which is known as Shy Guy Bazaar. This course features multiple Super Mario Bros. 2 references, such as Shy Guys riding on magic carpets and vases.
Mario Kart 8
Both the playable Shy Guy and regular Shy Guys appear in Mario Kart 8. A course themed after them, known as Shy Guy Falls, appears as the final course in the Flower Cup. They also have a business known as Shy Guy Metals, which has been going "since 1987" (a nod to their first appearance in the non-Mario game, Yume Kōjō: Doki Doki Panic). An advertisement for this business can be seen in the Flower Cup's second track, Toad Harbor. In the factory course, Shy Guys can be shown working outside, though the playable Shy Guy only comes in red.
Mario vs. Donkey Kong series
Mario & Luigi series
Mario & Luigi: Superstar Saga
Since this game takes place in the far-away Beanbean Kingdom, Shy Guys are absent. However, subspecies of them, such as Chuck Guys and some subspecies of Snifits appear. A species named Gunner Guy also appears in Bowser's Castle.
Mario & Luigi: Partners in Time
In Mario & Luigi: Partners in Time, a species of Shy Guy called Boom Guys appear in Baby Bowser's Castle. They are Shy Guys with Bill Blasters on their heads. Later in the game, Elite Boom Guys, stronger versions of Boom Guys, appear in the Gritzy Caves. Fly Guys also appear on Star Hill. A ghostly version of Shy Guy named Boo Guy also appears in the game, near Vim Factory; and a stronger, revamped version named Ghoul Guy appears in Shroob Castle.
Mario & Luigi: Bowser's Inside Story
“Shy Guy corps reporting. They got us. They got us all. We're such bad soldiers!”
In Mario & Luigi: Bowser's Inside Story, several Shy Guys can be found in Bowser's Castle, and a new Shy Guy character, Sergeant Guy is introduced. A group of Shy Guys aid Bowser with the Shy Guy Squad attack, which has the Shy Guys push Bowser into a slingshot and flings him into an enemy. There are also Fawfulized variations of Shy Guys, called Fawful Guys and Dark Fawful Guys. A new subspecies of Shy Guys, Leaf Guys, also appear while fighting the Wiggler boss. Bowser can inhale them and they can be battled by Mario & Luigi.
Mario & Luigi: Dream Team
Shy Guys reappear as an enemy in Mario & Luigi: Dream Team. Shy Guys can only be fought after the Shy Guy Airtub they were inhabiting has been destroyed, and always appear in a group of three when battled at that point. They are never found on the field. In battle, they attack by bouncing to either side of Mario or Luigi, and running at them simultaneously. This can be dodged by jumping over or on to the Shy Guys.
A stronger variation of Shy Guys called Shy Guy Rs appear later on in the game.
Mario Pinball Land
In Mario Pinball Land, multiple colored Shy Guys appear in Frosty Frontier and Shifting Sands areas. In the area Frosty Frontier, Shy Guys skate around the screen and Mario has to hit them all to get a star. In the Shifting Sands area, Mario encounters them 3 times, once before he makes it into King Tut's pyramid and twice inside the pyramid. But he encounters them in the different places they all do the same method. When outside the pyramid, they hide behind cacti and run from cactus to cactus. As they run, Mario has to hit them. If he is able to hit them all, he gets a star. When inside the pyramid, the Shy Guys hide behind Vases instead of cactuses. Mario has to hit them all to get a switch to open in the floor so he can get to King Tut.
Shy Guy is an opponent at the puzzle game Yakuman DS. His default rank (Ranking mode) is 18, he has 1/5 of difficulty.
Mario Baseball series
“IT'S HORRIBLE! HIDE THE CHILDREN! LOCK THE DOORS! BOLT THE WINDOWS!”
Shy Guys of all different colors are playable in Mario Superstar Baseball. They are balanced characters. Ironically, their starting captain is Yoshi, one of their earliest enemies. They appear in Mario Super Sluggers, still on Yoshi's team.
In Mario Super Sluggers, all the Shy Guys have their fielding skills boosted a few levels, with the Black Shy Guy showing the best fielding abilities.
Regarding chemistry, in Mario Superstar Baseball, Shy Guys show good chemistry with Birdo and Monty Mole, while showing bad chemistry with Baby Mario and Baby Luigi. In Mario Super Sluggers, the Shy Guys maintain their good chemistry with Birdo and Monty Mole, but they also display good chemistry with Boo. Their bad chemistry has also be expanded in that their relationship with Yoshi, the Yoshi species, and, once again, Baby Mario and Baby Luigi.
Mario Strikers Charged
Shy Guys appear as sidekicks in Mario Strikers Charged. They are balanced players. Their skillshot is the Bullet Bill Blast. When given enough time, a Shy Guy will charge fully before riding a fast bullet bill aimed right at the goalie. When this move is performed, the goalkeeper and all players near him (including the Shy Guy) will be temporarily stunned. Shy Guy gets up more quickly than the other teammates, however, so he may quickly get to the ball and score. Other allies not affected by the blast may take the ball and score as well. Alternatively, an opposing player trailing the bullet bill (who was a safe distance away) may sweep through and pass the ball downfield to one of its teammates.
When Shy Guy scores, it does its own celebration. Sometimes it will run, trip, and its mask will fall off. Similar to the Mario Power Tennis trophy award. While this would seem to confirm that Shy Guys' masks are not their actual faces, but when Shy Guy scores, different facial expressions are shown on the mask. It makes a happy face and a mad face.
Mario & Sonic series
Mario & Sonic at the Olympic Games
Shy Guy is a referee in the Wii/DS crossover, Mario & Sonic at the Olympic Games. Shy Guy is seen in his normal outfit of red robes and randomly hosts events with a cast of other Mario and Sonic Characters.
Mario & Sonic at the Olympic Winter Games
Shy Guy appears in the audience in many events in Mario & Sonic at the Olympic Winter Games. A variety of colours can be seen, from the traditional red to new pink and light blue. In the DS version, they appear as the goalies in the Ice Hockey and Fever Hockey events. It also seems that Yellow Shy Guys tend to lie, except for one, who resides in Cubyrinth.
Mario & Sonic at the London 2012 Olympic Games
In Mario & Sonic at the London 2012 Olympic Games, Shy Guys appears during in the London Party and Story mode of in the Wii/3DS version.
Mario Sports Mix
Shy Guys reappear in Mario Sports Mix as goalkeepers in a Hockey game. When a player uses their special during a Hockey, Shy Guy will disappear when the special is happening and then reappear when it ends. Players can't control them but they can command shy guys to go after the puck by pressing .They also appear in the Western Junction court, where various Shy Guys throw either Banana Peels or Coins. They also appear in the crowd of Wario Factory in multiple colors.
Shy Guys first appear in Super Mario Bros. 2, where they are minions of the tyrannical king Wart and the 8 bits. However, their first appearance chronologically is in Super Mario World 2: Yoshi's Island where they are members of the Koopa Troop.
Since Super Mario Bros. 2, Shy Guys have been seen working for many other villains, including Smithy, Donkey Kong and Kamek. One Shy Guy (the White Shy Guy) is actually an ally of Yoshi. It can be assumed that Shy Guys never have had a true allegiance.
All Shy Guys (with the minor exception of General Guy) wear robes that can be red, pink, blue, yellow, green, light blue, black, or white. They are all fairly short and all wear masks with holes on them that represent eyes and a mouth. It is unknown what is behind these masks. However, in Shy Guy's trophy celebration movie in Mario Power Tennis, Luigi sees a Shy Guy without his mask on and is shocked at the sight. Also, in Luigi's Mansion, Luigi can use the Poltergust 3000 to pull a mask off a Shy Guy Ghost. These faces are pure blackness with two glowing yellow eyes. It is unknown whether this is what a Shy Guy's face looks like when it is alive, or it is simply a mirage, as they, like the game's other generic ghosts, were imitations created by Vincent Van Gore.
It is also possible that the Shy Guys' so-called "masks" are not masks at all, but rather faces. In Yoshi's Island DS, the sleeping Shy Guy's mask eye holes are closed, supporting this. Also, the Bandit sub-species of Shy Guy have been shown to have the ability to change the expressions on their masks as if they were their actual faces. The picture shown when Bandit wins in Super Mario World 2 Mini-Battles even suggests that he is able to stick out his tongue. Also, Super Mario RPG's Shy Guys' eye holes comically spin when the Shy Guy is confused, much like people's eyes do in cartoon gags; the Shy Guys of Super Mario RPG are also able to blush on their masks. Spear Guys and Dancing Spear Guys are perfectly capable of moving their mouth holes when chanting and singing, as Super Mario World 2: Yoshi's Island shows. Most recently, in Mario Strikers Charged, Shy Guys have been shown to yet again be perfectly able to change the expressions on their masks. However, most information suggests that Shy Guy's mask is indeed a mask, and what he hides behind is surely something very dark and secret.
Some early Super Mario Bros. 2 artwork of Shy Guys, as well as The Super Mario Bros. Super Show!, depicted Shy Guys as wearing strange, Chuckola Fruit-like badges depicting an angry face. It is unknown what this badge represents; it is possible that it is some kind of emblem to the 8 bits. Another Shy Guy-related element seen only in Super Mario Bros. 2. and The Super Mario Bros. Super Show! are also notable for using game artwork of the earliest forms of Shy Guys, making them tall, stout, and human-like; however, the appearance of Shy Guys was later redesigned to their in-game sprite appearance in Super Mario Bros. 2.
In the first few episodes of The Super Mario Bros. Super Show!, Shy Guys were depicted as being similar in appearance to their game counterparts, though with one large exception - their masks possessed only two holes. They only had eye holes perpetually in a scowling position. Later episodes of the show would have Shy Guys resembling their game versions more with three holes in their mask, all of which were perfectly circular.
Official profiles and statistics
Bio: Shy Guy's proud of his finely-honed style and loves to surprise people who underestimate him because of his height.
Mario Kart 7
Names in other languages