Green Shell

Green Shells are green Koopa Troopa shells that have appeared in many Mario games so far. Though their appearance remains largely the same, their functions differ throughout the different games.

Super Mario Bros
Green Shells first appear in Super Mario Bros.. After a Koopa Troopa is hit by a jump attack, it will retreat into its shell, leaving it for Mario to use it. Upon contact, the shell is launched, defeating every enemy in its way. However, this can also backfire when the shell rebounds from any obstacle. A shell in motion can be stopped by stomping on it. If a Koopa Troopa is seen wearing a Green Shell, that means that it will not turn around if it reaches a cliff and will instead straightly walk into it. The Koopa Troopa will stay in the shell for only a limited amount of time. After a while, the Koopa Troopa will get out of its shell and resume its business. Koopa shells could only get destroyed by a fireball shot by Fire Mario.

Super Mario Bros.: The Lost Levels
Green shells reappear in the Japan-only sequel Super Mario Bros.: The Lost Levels. Nothing has changed from the previous game; it can be obtained by again, defeating a Koopa Troopa and making it retract into its shell, making the shell available for use.

Super Mario Bros. 3
The Green Shells return in Super Mario Bros. 3 and they serve the same purpose as in the first game. The Shells can now also be grabbed and carried around before they are thrown, which can be used to hit blocks that can only be hit by the Shells.

Super Mario World
Green Shells appear in Super Mario World. However, instead of the Koopa Troopa retracting back into its shell, it will slide out of its shell, becoming a Beach Koopa. If the Beach Koopa finds its shell again, it will go back inside it. Green Koopa Shells do not give Yoshi any abilities unlike the other shells.

Super Mario 64 / Super Mario 64 DS
Green Shells (referred to as "Shiny Shells") are rare objects in Super Mario 64. When Mario jumps atop a green shell, the plumber can travel at fast speed and ram into enemies to defeat them instantly. Riding a shell also allows Mario to navigate over lava or water. Additionally, if Mario grabs a green shell while underwater, he can hold the shell in front of him and use it to swim faster in water for a short period of time. When riding on a Shiny Shell, there is the same music as the Wing Cap.

Shiny Shells/Green Shells make a return in Super Mario 64 DS, where they can be ridden on (and used underwater) once again. Some minigames found in Super Mario 64 DS require use of a Green Shell such as Shuffle Shell. Also Yoshi can eat the Shiny Shells and spit them out, although when hitting a wall it will disappear.

New Super Mario Bros.
Green Shells return in New Super Mario Bros. that can be obtained after stomping on a Koopa Troopa. Just like in Super Mario Bros., the Koopa will retract into his shell so Mario can grab the shell and throw it then. Aside from the design change, the Green Shell had little changes in its function. For example, Mario can stay afloat with the shell while in water.

In addition, it is also seen that Bowser Jr. throws green Koopa shells. The player must step on the green shell, pick it up, and throw it back at Jr. to stun him. Once stunned, the player can then attack Bowser Jr. by either jumping on him or ground-pounding him.

Super Mario Galaxy
Green Shells reappear in Super Mario Galaxy as an offensive weapon. Many Green Shells in this game will be found independently (usually underwater), though occasionally they will still be attached to the back of a Koopa Troopa, in which case the player must spin the Koopa Troopa or jump on its back to get it to retreat into its shell, after which it can be picked up and used normally. Unlike Super Mario 64, Mario can only hold the Green Shell, not surf around on it. Mario can throw the shell by spinning in a straight direction until it hits another object. The Green Shell moves in a straight line, and keeps going even if the Green Shell is thrown off the edge of a planet. Like Super Mario 64, Green Shells can be found underwater. Underwater shells can be grabbed by Mario, and allow him to swim faster. The Green Shell can also be thrown at underwater creatures to defeat them. The shell also produce light underwater, so the player could destroy underwater Boos and point at enemies after throwing the shell. The other two varieties of shells that appear in Super Mario Galaxy are Red Shells and Gold Shells. These act more or less similar to Green Shells, with a few minor differences.

New Super Mario Bros. Wii
Green shells make an appearance in New Super Mario Bros. Wii. They have the same function as in New Super Mario Bros.. If Ice Mario attacks a Koopa throwing an ice ball, the Koopa will remain frozen within his shell in an ice block. Mario can use the ice block with the shell within like a platform or lift it up to throw the block and destroy the shell in pieces. Also, larger green shells appear in World 5. Mario can enter these larger shells and find hidden items.

Super Mario Galaxy 2
Green Shells reappear in Super Mario Galaxy 2, with the same function as in the predecessor. However, in this game, only Green Shells appear, and Red Shells and Gold Shells do not. In this game, they are mostly found in galaxies such as the Cosmic Cove Galaxy and Slimy Spring Galaxy.

Super Mario 3D Land
Green Shells reappear in Super Mario 3D Land with the same function as other games, however, Mario can only kick the shell in this game and only green shells appear once again.

New Super Mario Bros. 2
Green Shells reappear in New Super Mario Bros. 2 with the same function as in the past New Super Mario Bros. installments. However, if Mario passes through a Gold Ring, any Green Koopa Troopas in the area turn Golden, and so do their shells. If thrown, they produce a trail of coins behind them.

New Super Mario Bros. U
Green Shells reappear in New Super Mario Bros. U with the same function as in the past installments.

Super Mario World 2: Yoshi's Island / Yoshi's Island: Super Mario Advance 3
Green Koopa Shells also appear in Super Mario World 2: Yoshi's Island, where they can be carried by Yoshi, but Yoshi cannot swallow them due to them being hard and inedible. These green shells act in the same manner as in Super Mario World; it can still hurt Yoshi when a shell sliding around and touches him.

Yoshi's Island DS
The Green Shells, worn by Koopas, re-appear in Yoshi's Island DS, where they are still inedible and can be used to attack enemies.

Paper Mario series
The Green Shells reappear in the Paper Mario series, where they are donned by Koopa Troopas once again. In Super Paper Mario, there is an item called Shell Shock, which is a giant 8-bit Green Shell (appearing in its design from Super Mario Bros.) which can be used to attack enemies the same way as a Green Shell would. However, the Shell Shock can still hit the heroes, which causes a certain number of damage depending on what level the player is on. In Paper Mario: Sticker Star, Green Shells appeared as stickers, under the name Shell Sticker. Mario can use a Shell Sticker to summon a Koopa Troopa and jump on it twice to send the shell sliding against foes. There is also a Shiny Shell sticker which is stronger and summons a red Koopa, and an even stronger Flashy Shell, which is blue and summons a Buzzy Beetle.

Mario & Luigi: Partners in Time
In Mario & Luigi: Partners in Time, the Green Shell is a Bros. Item that is used as a weapon against enemies. At least two bros. are required to use the item. When the item is chosen, one of the brothers will kick the Shell towards the foe. It will then bounce off the enemy, cause damage, and come to the other player. After each kick, the shell starts moving faster along the ground. The brothers can then repeat this until the player misses a kick, the enemy is defeated, or sixteen successful hits are dealt; in any one of these cases, the Green Shell disappears. When the adult and toddler Mario brothers fight together, the babies can sit over the shell and spin upon hitting the enemy, causing extra damage to the foe.

Mario & Luigi: Bowser's Inside Story
In Mario & Luigi: Bowser's Inside Story, the Green Shell is a Special attack for Mario and Luigi. It is used exactly as in Mario & Luigi: Partners in Time, but lacks the baby-button command. As the baby-button command lacks, the speed of the shell shows difference. Unlike in previous game, which the shell's speed had to be quite steady in order to activate baby button commands, the shell travels in a fast speed as it gets kicked and the speed decreases after it ricochets from the enemy. Similar to previous game, the returning speed of the shell increases after each kicks. This shell will continue to attack even if the first target was defeated, just like Red Shell in Partners in Time. It will break after ten hits. It costs three SP to use this attack. To use it, the player must get all the Trash Pit Attack Pieces. This is the first Special Attack the brothers get, as well as one of the few mandatory ones.

Mario Kart series
In the Mario Kart series, Green Shells appear as a projectile weapon. Racers can shoot Green Shells forward in a straight line to hit opponents. Unlike the Red Shell, the Green Shell is able to rebound from walls. After ricocheting several times, the Green Shell will automatically disappear. Aside from single Green Shells, this item also comes in a triple variant. When the player decides to use the item, a group of three Green Shells will rotate around the driver's kart (In Mario Kart 64, Mario Kart Super Circuit, Mario Kart DS, Mario Kart Wii and Mario Kart 7) protecting him or her from Bananas and other shells. If the player collides with another racer, the other racer will be hit by one, and if the other driver also has another set of Triple Green Shells or Triple Red Shells, both drivers will lose shells. Like ordinary Green Shells, they travel in a straight direction when fired and will bounce off walls for a time. In Mario Kart: Double Dash!!, they are a special item exclusive to Koopa Troopa and Paratroopa (and Petey Piranha and King Boo, due to their ability to have any special item). Also, in Double Dash!!, the three shells are carried rather than having them circle around the kart. Triple Green Shells are not used in Mario Kart DS Wi-Fi mode due to the fact that items cannot be deployed in that mode.

Super Mario Kart
In Super Mario Kart, the Green Shell is an item in the form of a missile. When the player uses this item, it will fire directly forward of the player's kart, only changing direction if it hits a wall. Alternatively, the player can place the shell on the track behind them like a Banana. The Green Shell will be destroyed once it hits a kart, another item, or falls off the race track or into water or lava. If the shell hasn't been destroyed or fallen off the track, the game engine will remove it after more items are released onto the track. When a kart is hit by a Green Shell, the kart will stop dead in its tracks whilst spinning out, unlike a Banana where it would continue to move for a short while. The only computer-controlled player with the ability to use a Green Shell is Koopa Troopa, but instead of Koopa throwing the shell, it is thrown through the air in the same manner as a Banana, and stops dead when it lands rather than sliding across the ground. Green Shells do not bounce over jumps, for example, firing a Green Shell towards the main jump in Mario Circuit 2 will make the shell bounce back after hitting the wall, rather than clearing the jump and landing on the track section over the wall.

Mario Kart 64
In Mario Kart 64, the Green Shell acts the same way as the previous game, however, when the player holds the analog stick backwards, the shell will now be fired backwards instead of dropped. Computer-controlled opponents do not receive this item in the game, their items being relegated to Bananas, Fake Item Boxes, Stars and Thunderbolts. When a player is hit by a Green Shell, they will topple over for roughly two seconds before stopping. This crash effect also affects the computer-controlled players whilst off-screen, whereas a computer opponent being hit with a Red Shell, a Fake Item Box, a Star, or a Chain Chomp (the latter only being on Rainbow Road) off-screen will simply make the computer-controlled player stop and continue to move immediately afterwards in the form of a cheat.

An alternate item called the Triple Green Shell also debuts in Mario Kart 64. When this item is activated, three shells form a circular barrier around the player's kart in a similar way to the balloons in Battle Mode on the previous game, which can be used to guard against items and projectiles, as well as turning the kart into a battering ram against other karts. Unlike the single Green Shell however, these shells cannot be fired backwards, and are slightly harder to aim as they are constantly rotating around the kart.

Mario Kart: Double Dash!!
In Mario Kart: Double Dash!!, the Green Shell is weaker in the way it can now be destroyed after hitting a certain amount of walls. Also, when fired backwards, it moves much slower than forwards, unlike Mario Kart 64 where the shell moved at the same speed in both directions. The physics has also been changed from the previous game, and being hit by a Green Shell will simply topple the player's kart, letting them continue moving straight away. The Triple Green Shell variant is also in this game, but only Koopa Troopa, Koopa Paratroopa, King Boo and Petey Piranha can receive this item, as it is now classed as a Special item. Unlike Mario Kart 64 however, instead of the shells rotating around the player's kart, they are held in the character's hand, and as such, they cannot be used as protection against track-based obstacles unless they are fired; also, a shell will travel through a Fake Item Box without destroying either of the two. Also, the Triple Green Shell can now be fired backwards, a feature missing from Mario Kart 64. Characters who otherwise cannot receive a Triple Green Shell can steal this item from another kart by ramming it while using a Mushroom. Also, computer-controlled players can now receive, and fire, any item in the game from any position.

Non-moving Green Shells also make their first appearance since Super Mario Kart. If a player holding a Green Shell or Triple Green Shell is hit by a Blue Spiny Shell, a Bob-omb, a Thunderbolt or a Star, the shell(s) will be dropped onto the track. Yoshi Eggs and Birdo Eggs may also randomly release this item after being destroyed. Certain track obstacles may also make a kart lose their items, such as Piranha Plants, Chain Chomps, Cataquacks and cars and trucks. Also, certain creatures on some race tracks can be temporarily taken out by shells, such as Goombas and Cataquacks. If a pipe containing a Piranha Plant is hit, the Piranha Plant droops down and temporarily cannot attack passers-by.

Super Smash Bros. series
Green Shells also appear in the Super Smash Bros. series. A Green Shell is a regular item which can be picked up and thrown at other fighters, damaging them. The shell can also be activated by hitting it or jumping on top of it, which causes the shell to shoot in a certain direction, damaging any characters in the way.

Mario Strikers series
Green Shells, as well as Giant Green Shells, appear as offensive power-ups in the Super Mario Strikers and Mario Strikers Charged. In these games, they are normally collected in groups of three. Once used, they are fired out in the direction the soccer player is facing. The Green Shell then trips up any opponent it hits on the ground, thus halting their movements for a small period of time. The shells, unlike the Red Shells, do not home in on a target, but instead move in one straight path until the shell hits a wall, which makes them bounce back, or hits a player, which destroys the shell. The aforementioned Giant Green Shells cover a wider range than the regular Green Shell. They are useful for clearing room for a Super Strike or Mega Strike.

Mario Tennis series
Green Shells appear only in the game Mario Power Tennis for the Nintendo GameCube and Wii. These staples can be used during an Item Battle match, which can be obtained when the player hits an Item Box with the ball over the net. If the player hits the ball after received the item, he or she fires three green shells at the same time towards opponent's field to stumble any player with them so that they cannot respond for the incoming ball. Just like in other games, green shells work going in straight lines, but if they cannot hit any target on their way, they simply disappear after used.

Super Princess Peach
Green Shells also appear in Super Princess Peach. They can be obtained by knocking Koopas out of their shells, allowing Peach to throw it to attack enemies. Every consecutive enemy Peach hits with the shell can leave coins and Large Coins in their wake.

Mario Sports Mix
In Mario Sports Mix, Green Shells appear again. When used normally, they'll move at a straight line, and temporarily knock out anyone in their path. When combined with a ball/puck, the object will move at a straight line at high speeds. This makes the item rather dangerous in dodgeball, since players can't catch, nor repel a dodgeball while it's equipped with an item.

Mario & Sonic at the London 2012 Olympic Games
During the Dream Hurdles event in Mario & Sonic at the London 2012 Olympic Games, two Green Shells can appear if the player pushes a ? Switch. Getting hit with one results the player losing five points.

The Legend of Zelda series
The Green Shell's Reference also appears in The Legend of Zelda: Phantom Hourglass as enemies in Mutoh's temple. They are very easy to defeat as they die in a few hits.

Trivia

 * A green Koopa Shell was one of many collectible treasures that Kirby discovered in "The Great Cave Offensive" mode of the games Kirby Super Star and Kirby Super Star Ultra. Kirby found the Koopa Shell in the Old Tower Area of the Great Cave. The Koopa Shell was worth 800 Gold.
 * In the Mario Kart series, when thrown backwards, a Green Shell is better than a Red Shell, since the red variation gets destroyed upon hitting a wall, and when it's been thrown backwards, it doesn't home in on opponents. Of course, this doesn't apply to Mario Kart Super Circuit.
 * If the Question Block AR Card is used in the Fishing minigame included as part of the Augmented Reality Games software on the Nintendo 3DS, and the card is placed on a green surface, Green Shells will rain down upon the water. The shells can also be caught by the player.
 * In Super Mario Chess, Green Shells appear as pawns on Bowser's team.