Big Boo

"I may not be the king, but I sure am BIG. Big enough to crush you!"

- Big Boo

Big Boos, also known as Atomic Boos, are a species of Boo. Usually, they resemble and behave similarly to normal Boos, except they are larger and stronger.

Super Mario World
The Big Boos (parsed The Big “Boo” in-game) first appear in Super Mario World. In the game, Big Boos inhabit the various Ghost Houses located around Dinosaur Land. They first appear in Donut Secret House. They are four times bigger than a normal Boo in both height and width, but still have the same mannerisms of their smaller counterparts, meaning that when looked at, they hide behind their arms, occasionally peeking to see if they are still being looked at. However, if Mario or Luigi's back is turned, a Big Boo attacks them from behind.

In the game, Big Boos are much more difficult to pass than their smaller brethren. As such, Mario or Luigi usually have to use a trampoline to jump over these massive ghosts. However, if Mario or Luigi can get a running start, they can usually Spin Jump over a Big Boo. Additionally, if there is room, the brothers can use a Cape to fly over a Big Boo or perform a sliding attack during descent to actually destroy the Big Boo.

In Super NES-era Player's Guides, the Big Boo enemy is known as Big Blue Boo to differentiate from the Big Boo boss.

Big Boo also appears as a hidden boss of the Donut Secret House. This Big Boo does not hide when Mario or Luigi is facing him, but periodically changes from invisible to visible. He can be defeated by throwing Grab Blocks at his face while he is visible. This boss does not damage Mario or Luigi, but two normal Boos accompany him. Once the Big Boo is defeated, a new path is revealed on the overworld, leading to the Star World. Unlike the Koopalings and Reznors, the Big Boo can be fought again at any time in the original without the use of the and  buttons on the map.

During development, when "Boo" Buddies were still referred to as "Boo" Diddly, the name for the Big "Boo" was originally going to be localized as "Boo" Jackson, a reference to multi-sport athlete.

Super Mario 64 / Super Mario 64 DS
Big Boos return in the game Super Mario 64. Again, a Big Boo disappears when looked at and becomes visible again when Mario turns away. Big Boos have a high pitch laugh like a normal Boo, but they make the same low pitch grunt as a Thwomp does (changed to the sound made when a platform drops in the DS remake) when hit. If these Boos attack Mario, he loses three wedges of health. They use the same model as normal Boos but enlarged.

Big Boos can be attacked only when visible, so Mario has to attack these massive ghosts by either ground-pounding them from above or punching them from the side. There is one Big Boo in the courtyard. This one is larger than the other Boos in the courtyard, but only slightly so. If Mario kills this one, it drops a cage, leading to Big Boo's Haunt. In this course, Mario can fight three larger Big Boos. These Big Boos take three hits to defeat, becoming smaller after each hit. However, if the player leaves the area before completely defeating a Big Boo, the Big Boo's health resets. After destroying a Big Boo, Mario receives a Power Star.

In the Japanese version, the name of the standard Big Boo translates to "Boss Boo," and the name of the one that appears when all of the house's Boos are defeated translates to "Master Boo."

The original version of Super Mario 64 shows the Big Boo's laugh in the mission Go on a Ghost Hunt as "Ka ha ha ha!" in the text box. In the remake, "Ha ha ha ha!" is written instead.

In Super Mario 64 DS, Big Boos play the same role as in the original, but the boss ones now have their own, more sophisticated model and are faster. Yoshi cannot defeat Big Boos due to low attack power, just like the normal Boos. He also cannot lick them up. Due to his inability to enter Big Boo's Haunt, this can only be seen without manipulating the game with the smaller one in the courtyard. King Boo also makes an appearance and shares an internal model with the Big Boo, though while he retains his crown from Mario Kart: Double Dash!! and characteristic cackle, he is erroneously referred to as "Big Boo" in English versions.

Super Mario Sunshine
Big Boos do not directly appear in Super Mario Sunshine; however, Sleepy Boos are identified as Big Boos in the Versus Books guide, and the Golden Boo in Episode 2 of Sirena Beach is also described as a Giant Boo statue. A boss known as King Boo appears to be based on a Big Boo.

Super Mario Advance 4: Super Mario Bros. 3
In Super Mario Advance 4: Super Mario Bros. 3, a Big Boo appears in the first room of the World-e level Vexing Doors. The Super Mario World boss also appears at the end of the level, as well as a previous level, Doors o' Plenty. Additionally, unused sprites in the game show the Super Mario World 2: Yoshi's Island iteration of the enemy, specifically using alternate sprites that were likewise unused in the source.

Super Mario Galaxy
In Super Mario Galaxy, one Atomic Boo appears in the "Boo in a Box" mission. It uses a model separate from the regular Boo (labeled "TeresaChief"; compare "KuriboChief"), but the object is scaled at nearly one-third its native size in the game itself. Despite this, it is still visibly bigger than regular Boos. The Atomic Boo must be lured into the light to defeat it and obtain its Power Star.

An individual Atomic Boo named the Spooky Speedster is found in two areas of the game. Mario must race him twice to win a Power Star: once in the Ghostly Galaxy and once again in the Boo's Boneyard Galaxy.

New Super Mario Bros. Wii
Big Boos reappear in the game New Super Mario Bros. Wii, and act much like they do in Super Mario World. They can only be encountered in Ghost Houses, and are usually seen with many smaller Boos. Unlike regular Boos, a Big Boo does not stop attacking unless every player is facing it, unless there are 4 players, in which case, only 3 need to face it.

Super Mario Galaxy 2
In Super Mario Galaxy 2, Big Boos make an appearance using a different model (labeled "TeresaAtomic"). They go under the name Mega Boo or King Boo.

In this game, they follow Mario through a thin hall, not stopping unless they are looked at or the player reaches a Power Star or Launch Star. Mega Boos are only found in groups of five, with the Mega Boo in the middle being larger than the ones surrounding it. Mega Boos are only seen in Sneaking Down the Creepy Corridor in Haunty Halls Galaxy.

The version of Atomic Boo from Super Mario Galaxy is an unused leftover with its model deleted from the game data.

Super Mario 3D Land
These gigantic Boos reappear in Super Mario 3D Land, where they behave similarly to their New Super Mario Bros. Wii counterparts. They appear in a few Ghost Houses. Sometimes, if Mario is very far away from the Big Boo and looks in the opposite direction, it floats away instead of drifting towards him.

New Super Mario Bros. 2
Big Boos reappear in the Ghost Houses of New Super Mario Bros. 2. They can be turned into Gold Big Boos by passing through a Gold Ring. While in their golden form, they cover their faces and leave a trail of coins behind them for Mario to take. Whenever it covers its face, the Big Boo glows red, while it radiates a dark shadow around it once Mario stops staring at it.

This game introduces a new type of Big Boo known as Boohemoth.

New Super Mario Bros. U
Big Boos reappear in the Wii U title New Super Mario Bros. U, once again only appearing in Ghost Houses. Nothing changes about their behavior, but if the player looks at a Big Boo they will begin to sweat.

Super Mario 3D World / Super Mario 3D World + Bowser's Fury
Big Boos also appear in Super Mario 3D World and its Nintendo Switch port Super Mario 3D World + Bowser's Fury with the same behavior of Super Mario 3D Land. Some can be seen outside the windows in Ghost Houses watching the player, but these Big Boos do not do anything special. Big Boos can now be defeated by Light Boxes, leaving coins.

Super Mario Maker / Super Mario Maker for Nintendo 3DS / Super Mario Maker 2
Big Boos reappear in Super Mario Maker, Super Mario Maker for Nintendo 3DS, and Super Mario Maker 2. The player can enlarge a normal Boo with a Super Mushroom, transforming it into a Big Boo although being slightly smaller than in other games, similar to the Yoshi's Island games. The player can also give them wings which make them slightly faster. They can also be put in Clown Cars, Lakitu's Cloud and on tracks.

Super Mario World television series
Big Boos appeared in two episodes of the Super Mario World animated series. In the episode "Ghosts 'R' Us", Yoshi, while exploring Wizenheimer's haunted house, encounters a Big Boo and three regular Boos. Terrified of the Boos, Yoshi proceeds to run away in a panic as the four ghosts give chase. After running some time through the haunted house and losing the three regular Boos, Yoshi manages to trick the Big Boo into entering a vacant room. With the Big Boo apparently trapped in this room, Yoshi locks the door. Unfortunately, the Big Boo simply phases through the wall and resumes chasing Yoshi. Yoshi eventually escapes his Big Boo tormentor by fleeing into the basement of the haunted house.

In Super Mario World's final episode, "Mama Luigi", a Big Boo is seen acting as a guard to Neon Castle, likely a misinterpretation of Bowser in the Koopa Clown Car flying over it in the game's map. Mario, Luigi and Yoshi easily sneak past this Big Boo guard by using a nearby Warp Tube, which leads to the basement of Neon Castle.

Super Mario Adventures
An unnamed Big Boo was also featured prominently in the Super Mario Adventures comic by Nintendo Power. After being lured into a Ghost House, Mario and Luigi, after an encounter with several dozen Boos, encounter a Big Boo. Attempting to stare down this Big Boo and the swarm of Boos, Mario and Luigi become exhausted after hours of simply staring at the shy ghosts. Nearly collapsing of exhaustion, Mario spots a door and, dragging Luigi, dashes to it, with the Boos and Big Boos after him. Bursting through the door of the room Mario and Luigi just entered, the Big Boo and his Boo minions are surprised to see Mario dressed as a doctor, with Luigi as his nurse. Acting as a psychiatrist, Mario manages to learn that, as a child, this Big Boo was constantly bullied, which led to its vicious behavior. After hearing this Big Boo's sad tale, Mario gives some helpful words of wisdom and advice. The Big Boo, having become a changed ghost through Mario's therapy, happily leads Mario out of the Ghost House and gratefully thanks him as Mario, Luigi, and Yoshi take-off to Bowser's Castle. Another Big Boo was later seen among the attendees to Bowser's wedding to the brainwashed Princess Toadstool.

Yoshi's Safari
The Big Boo appears as the boss of the level Ghost Mansion in Yoshi's Safari, Mario must shoot it with the Super Scope as he makes parts of the wall fall down on him. Later the Boo separates into three Circling Boo Buddies. Mario must shoot the one with his tongue out to win.

Super Mario World 2: Yoshi's Island / Yoshi's Island: Super Mario Advance 3
In Super Mario World 2: Yoshi's Island, they appear in many Towers and Castles. However, in this game, they are only twice as large a normal Boo in height and width, making them half as large as the ones in Super Mario World. Like normal Boos, they could only be defeated by looking away from the ghost and bouncing an egg off a wall, hitting the ghost in the face. They release Stars when defeated. Additionally, one of the bosses, Bigger Boo, starts as a normal Big Boo before being transformed by Kamek's magic.

Yoshi Topsy-Turvy
In Yoshi Topsy-Turvy, Big Boos appear in the Tale of the Spirit of Kindness and the Tale of the Spirit of Fright. They are much more common than the smaller Boos, which are only in the latter.

Yoshi's Island DS
Big Boos re-appear in Yoshi's Island DS, behaving the same way as they did in the original Yoshi's Island. One Boo-like enemy is transformed by Kamek into a boss, named "Hector the Reflector."

Yoshi's New Island
Big Boos reappear in Yoshi's New Island, acting the same way they did in previous Yoshi games.

Hotel Mario
In Hotel Mario, Big Boos first appear in Ludwig's Thump Castle Hotel and are powerful enemies, being about one-sixth the size of a hotel floor, but are slower than normal Boos. Big Boos in this game attack in a manner similar to the ones of Super Mario World, slowly floating towards Mario or Luigi when they look away, stopping and hiding behind their arms when directly looked at. Unlike the game's normal Boos, they are never transparent. When the player character is in a room or elevator, the Big Boo will lose track of them and wander in simple diagonal movements with a slightly confused expression.

Super Mario RPG: Legend of the Seven Stars
In Super Mario RPG: Legend of the Seven Stars, one Big Boo has a cameo appearance in this game - It is used in Bowser's Terrorize attack. While there is an enemy called "The Big Boo", it is in fact a misnamed regular Boo.

Mario Party
A Big Boo appears in Pedal Power, and the player must pedal a bike to start up a light bulb before the Big Boo catches them.

Mario Party 2
In Mario Party 2 a Big Boo appears in the Horror Land stage. As a typical Boo, it is able to steal objects from player's rivals, being coins or stars. However, Big Boo deals for stealing the coins or the stars from all the opponents, while paying to him three times the amount of coins than a normal Boo would do. Characters can ask for him only in night time; in daytime, Big Boo appears as a giant Boo statue. Since Big Boo can only be visited at night after taking a path that requires the Skeleton Key, meeting him proves to be a difficult and rare opportunity for players, especially during "Lite Play" mode.

In Mario Party Superstars, King Boo replaces Big Boo from the original Horror Land board.

Mario Party 4
In Mario Party 4, Big Boo reappears in the board Boo's Haunted Bash, having the same role as in Mario Party 2. In the game, it appears in an odd blue color. It appears when the two Happening Spaces at the top right of the board are activated three times. The Gaddlight has no effect on it.

Mario Party-e
In Mario Party-e, a Big Boo appears in Bolt from Boo, where two players must outrun it. If it catches Mario, the game is over. It uses its sprite from Super Mario World.

Game & Watch Gallery series
Big Boo is an opponent in the Modern version of Boxing from Game & Watch Gallery 4. He is Luigi's second opponent. However, instead of boxing gloves, Big Boo uses smaller Boos to pummel his opponent.

Paper Mario: The Thousand-Year Door
Atomic Boos make their Paper Mario series debut in Paper Mario: The Thousand-Year Door, with a single one appearing as an optional mini-boss in Creepy Steeple. It closely resembles the sprite of Bigger Boo, similar to how normal Boos in this game are based on its artwork. This Atomic Boo is composed of approximately two hundred different Boos. Mario can only fight it by going to the Creepy Steeple after freeing the 200 Boos in Chapter 4 (if he guesses the number right, a Boo gives him an Ultra Shroom). Even though Mario agrees to be nice to the Boos, they swarm him as soon as they are free. If Mario disperses those Boos a few times with the spin ability of his Super Hammer, the Boos combine together to form the Atomic Boo.

The Atomic Boo attacks by flinging Boos at Mario, charging up a powerful glare attack, hiding his face and becoming invisible like regular Boos, floating over and falling onto both Mario and his partner, and inflicting Mario with status ailments such as confusion and paralysis. In the battle with Atomic Boo, Mario's audience consists of solely Boos. Once Atomic Boo is defeated, it drops the Lucky Start badge that Mario can collect, and the Boos stop their swarming, appearing as normal enemies.

A graphic of a Dark version of Atomic Boo is unused. It is reasonable to assume that it would have been a more powerful version of Atomic Boo.

It is possible for it to drop the Lucky Start badge down the hole revealed by pushing the star statue. If this happens, it can be purchased from the Lovely Howz of Badges for 70 coins.

It is also worth noting that, despite being made of 200 Boos, it is still smaller than Boolossus, which is made of only fifteen. The Big Boo of Luigi's Mansion: Dark Moon, however, is roughly the same size as the Atomic Boo, and is made from ten Boos.

Super Paper Mario
Atomic Boos appear infrequently in Super Paper Mario. Only one appears in Merlee's Mansion, where it is considerably weaker than the one encountered previously. This Atomic Boo attacks the player by charging at them while they are facing away from them, turning intangible if it is faced. As such, it attacks like the Big Boos of the Super Mario series, albeit somewhat slower than usual, as well as being susceptible to jumps. Multiple Atomic Boos occasionally appear in the Mansion Patrol minigame; though slower than regular Boos. Defeating one gives many more points than defeating a regular Boo.

Paper Mario: Sticker Star
In Paper Mario: Sticker Star, the enemy is referred to as Big Boo, and it looks like a large, crumpled paper ball with a Boo face to go with the game's paper motif. The Big Boo only appears once in the entire game and is a mini-boss found in World 4. It is formed when Kamek combines the Boos found in the Enigmansion.

In battle, the Big Boo's only attack is eating Mario and then spitting him out. However, once the Big Boo uses its turn, the candles light up and the Big Boo turns invisible. During this time, Mario is unable to attack the Big Boo, but the Big Boo is still able to hurt Mario. In order to make the mini-boss visible again, a Thing sticker with wind or water properties needs to be used in order to extinguish the candles. However, using a Thing sticker with fire properties such as Matches and Lighter while the candle is put out relights it. Although the Big Boo is invisible while the candle is lit, it can still take damage from Spike Helmet or Poison Mushroom.

Once the Big Boo has been defeated, the Book of Sealing stays on its pedestal and the mansion is free of ghosts.

Luigi's Mansion
Big Boos do not directly appear in Luigi's Mansion; however, a boss known as Boolossus is based on a Big Boo, being an enormous Boo made of 15 smaller Boos.

Luigi's Mansion: Dark Moon
In Luigi's Mansion: Dark Moon, a Big Boo is one of the three bosses fought in Treacherous Mansion, the final mansion in the game, in the mission Ambush Maneuver. Luigi and E. Gadd were tricked by King Boo to come into the miniature train station inside the Train Exhibit, because E. Gadd thought that King Boo was there along with Mario's painting. Ten Boos are inside a mini train display in which they come together to form into Big Boo. The 10 Boos that assemble together are the only ghosts in the game who are not sucked into the Poltergust 5000, as they are trapped in the trains' cages and later placed in the Boo Canister by E. Gadd.

In battle, the Big Boo has three attacks. Its first attack involves it trying to crush Luigi from above. It attempts to crush Luigi three times in a row. If it misses all three times, it is momentarily dazed from hitting his face on the ground the third time. Its other attack involves hiding halfway in the ground and attempting to charge into Luigi from there. If it misses Luigi and hits the moving train, it is stunned. However, if it misses Luigi and the train, it just floats back into the arena. When separated into individual Boos, they can ram into Luigi. The third attack happens only if Luigi pulls back on Big Boo's tongue for too long, in which the boss will recover and ram into Luigi. This attack is also used by the Boos.

To defeat Big Boo, Luigi has two different methods of attacking it. The first one involves avoiding Big Boo while it slams into the ground three times before becoming stunned. Luigi has to pull Big Boo's tongue and launch it into the drill of the moving toy train. The other way is to make Big Boo dash slightly in front of the train. When the Big Boo hits the drill on the train, he splits into ten Boos. Luigi must pull their tongues and send them flying towards the carriages of the train. When one of them hits a carriage, that Boo gets imprisoned inside the carriage and is unable to escape. Once all of Boos have been imprisoned in the carriages, the mission is complete and the Pixelator takes Luigi out of the train display and back to the Bunker. Afterwards, E. Gadd Pixelates the Boos into the Boo Canister.

Although it is named "Big Boo" in English versions of the game, it shares the same Japanese name as Boolossus.

Mario Pinball Land
In Mario Pinball Land, Big Boo is one of the five bosses. He appears in the haunted house at the Fun Fair. He has the last Star Key. To defeat him, Mario has to attack him from behind. He has no direct attacks, but instead approaches Mario continuously. If Mario comes into contact with Big Boo from the front, he temporarily spins out of control as if in a daze.

Super Princess Peach
Big Boos also appear in Super Princess Peach. Unlike normal Boos, they are invincible. However, they can be stunned permanently by leading one to a ray of light, which only appears in World 3-2. When they are stunned, they are harmless and can be used as platforms. This game also introduces a new Big Boo species, the Mad Big Boo. Like normal Mad Boos, they stay still when Peach turns away from one, and chases after her when she looks at it.

Mario Golf: World Tour / Mario Sports Superstars
In Mario Golf: World Tour and Mario Sports Superstars, whenever Boo gets an Eagle, Albatross, or Hole-in-One, the animation shows multiple Boos who mix it in to form a Big Boo.

Captain Toad: Treasure Tracker
Big Boos reappear in Captain Toad: Treasure Tracker and its Nintendo Switch and Nintendo 3DS ports with only a few tweaks from Super Mario 3D World. While they act the same by following a Toad when they are not being watched, they are far less a threat due to the headlamp Captain Toad and Toadette have, which can destroy them. Additionally, using a Double Cherry to shine two headlamps on a Big Boo will defeat it much faster, within one second. To compensate for this, Big Boos generally appear in groups of two or more.

Mario & Luigi: Superstar Saga + Bowser's Minions
Big Boos appear in Mario & Luigi: Superstar Saga + Bowser's Minions, where they are enemies and recruitable allies found in Minion Quest: The Search for Bowser. They are flying troopers, and attack by running into enemies. Their Special Skill, Piercing Projectile, allows them to spit a blue beam at an enemy. Big Boos are slow, but have high HP and power. Their model bears a resemblance to King Boo's appearance from Mario & Luigi: Paper Jam.

Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey
Big Boos reappear in Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey, where they are enemies and recruitable allies found in Bowser Jr.'s Journey. However, the player can only befriend a maximum of two, meaning that the player would have to get rid of one of them after completing a level that involves them as enemy troops.

Mario Tennis Aces
A Big Boo appears in Mario Tennis Aces as the referee in Mirage Mansion.

Super Mario World

 * Super Mario World instruction booklet: You may remember the Boo Buddies from Super Mario Bros. 3. This time there's a whole horde of them! And amongst them there's a huge spook called The Big Boo. But don't worry, if you look at them, they act shy and turn away. Cute, aren't they? But watch it ... they're dangerous!

Super Mario World 2: Yoshi's Island

 * Official Nintendo Player's Guide: Just like a monster in the movies, Big Boos like to sneak up from behind when Yoshi's not looking.

Mario & Luigi: Superstar Saga + Bowser's Minions

 * Minion Quest: The Search for Bowser profile: A big ol' Boo. It's slow, but it flies and has incredible HP and POW.

Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey

 * Bowser Jr.'s Journey profile: An incredibly large Boo. What it lacks in speed it more than makes up for in stamina and power.