Big Boo

Big Boos, also called Atomic Boos, are a sub-species of Boo. Usually they resemble and behave similarly to normal Boos, except that they are larger.

''Super Mario World
Big Boos first appeared in Super Mario World. In the game, Big Boos inhabited the various Ghost Houses located around Dinosaur Land. Curiously, although they are over ten times bigger than a normal Boo, Big Boos still have the same mannerisms of their smaller counterparts. Of course, this means that when looked at, a Big Boo will fade and hide behind its arms. However, if someone's back is turned, a Big Boo will attack him or her 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 Cape Attack during descent to actually destroy the Big Boo. In the game, the ghost's proper name is "Big Blue Boo". Additionally, a translucent white one called "The Big Boo", is a hidden boss of the Secret Donut Plains Ghost House. He could be defeated by throwing Grab Blocks at his face. He had two normal Boos accompany him in battle.

Super Mario 64/''Super Mario 64 DS
Big Boos return in the game Super Mario 64. Again, a Big Boo would disappear when looked at, and become visible again when Mario turns away. Big Boos can only be attacked when visible, so Mario had to attack these massive ghosts by either Ground Pounding them from above or punching them from the side. Regular Boos first appear in the courtyard of Princess Peach's Castle, and act the same way except less aggressive and requiring only one hit. One Boo is the keeper of Big Boo's Haunt, a miniature ghost house that shrinks the one who enters. Inside the ghost house, Mario can fight three more Big Boos. These Big Boos take three hits to defeat, becoming smaller after each hit. After destroying a Big Boo, Mario will receive a Power Star. In the Japanese version, the giant Boos are known as "Boss Teresa" rather than "Atomic Boo" (Big Boo's Japanese name). The giant Boo that appears when all the ghost house Boos are defeated is referred to is also known as "Master Teresa."

In the DS remake, Super Mario 64 DS, the leader of the Boos himself makes an appearance. In this game, King Boo has his trademark crown from later appearances and characteristic cackle. However, in game, he is erroneously referred to as Big Boo in English versions.

''New Super Mario Bros. Wii
Big Boos reappear in the game New Super Mario Bros. Wii, and act much like they did in Super Mario World. They can only be encountered in Ghost Houses, and are usually seen with a lot of smaller Boos. Unlike regular Boos, a Big Boo will not stop attacking unless every player is facing it.

''Super Mario Galaxy 2
In Super Mario Galaxy 2, Big Boos follow Mario through a thin hall, not stopping unless they are looked at or the player reaches a Power Star or Launch Star. Big Boos are only found in groups of five, with the Big Boo in the middle being larger than the ones surrounding it. Big Boos are only seen in 'Sneaking Down the Creepy Corridor' in Haunty Halls Galaxy.

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 Wizardheimer'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 Wizardheimer's 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 Wizardheimer's Haunted House.

In Super Mario World's final episode, "Mama Luigi", a Big Boo is seen acting as a guard to Neon Castle. Mario, Luigi and Yoshi easily sneak past this Big Boo guard by using a nearby Warp Tube, which led 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.

''Hotel Mario
In Hotel Mario, Big Boos, first appearing in Ludwig's Thump Castle Hotel, are powerful enemies, being about one-sixth the size of a hotel floor; Big Boos in this game attacked in a manner similar to the ones of Super Mario World, slowly floating towards Mario or Luigi when they look away, turning transparent when directly looked at.

''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. The enemy, the Big Boo, is just a misnamed regular Boo.

''Super Mario World 2: Yoshi's Island
In Super Mario World 2: Yoshi's Island, they appear in many Towers and Castles. However, in this game, they are only about three times bigger than a normal Boo, unlike 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.

''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 will separate into three smaller Boos. Mario must shoot the one with his tongue out to win.

''Yoshi's Island DS
Big Boos re-appear in Yoshi's Island DS, behaving the same way as they did in the prequel.

''Paper Mario: The Thousand-Year Door
Big Boo reappears in Paper Mario: The Thousand-Year Door, now renamed Atomic Boo. The Atomic Boo is an optional mini-boss composed of approximately two hundred different Boos. To fight this boss, Mario must go to the Creepy Steeple after freeing the Boos in Chapter 4 and agreeing to be nice to them, after which all the Boos will come out and swarm him. If Mario knocks the Boos away twice with the Super Hammer by using the Spin Attack, the Boos will combine together to make the Atomic Boo. 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. Once Atomic Boo is defeated, he will relinquish his Lucky Start badge to Mario and the Boos will stop their swarming and appear as normal enemies.

''Super Paper Mario
Atomic Boos are rare enemies in Super Paper Mario. In fact, only one appears in Merlee's Mansion, where it is considerably weaker. This Atomic Boo will attempt to attack the player by charging at them while they are facing the direction opposite of them and will turn intangible and shy away if the player faces it. Also in Super Paper Mario, Atomic Boos will occasionally appear in the minigame Mansion Patrol; though slower than regular Boos, Atomic Boos take several hits to defeat instead a single one.

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 will deal 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.

Mario Party 4
In Mario Party 4, Big Boo reappears in the board Boo's Haunted Bash. In the game, it appears in an odd blue color.

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

''Mario Pinball Land
In Mario Pinball Land, Big Boo is one of the four bosses. He appeared in the haunted house at the Fun Fair. He has the last Star Key. To defeat him, Mario has to attack him from behind.

''Super Princess Peach
Big Boo also appear in Super Princess Peach. Unlike normal Boos, they are invincible. However, they could 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 could be used to step on to reach a platform. This game also introduces a new Big Boos sub-species, the Mad Big Boo. A Mad Big Boo is a Big Boo under the Vibe Scepter's power. Like normal Mad Boos, they stay still when Peach turns away from one, and chases after her when she looks at it.

Notable Big Boos

 * King Boo - ''Luigi's Mansion
 * Bigger Boo - ''Super Mario World 2: Yoshi's Island
 * Boolossus - ''Luigi's Mansion

Gallery
 File:BigBoo_SMW.png|Super Mario World File:BigBooSM64.png|Super Mario 64 File:BigBoo.PNG|New Super Mario Bros. Wii File:Mg10.jpg|Super Mario Galaxy 2 

Trivia

 * A purple variant of Atomic Boo, called Dark Atomic Boo, was found in the coding of Paper Mario: The Thousand-Year Door, but cannot be encountered. It would have been fought on the 50th floor of the Pit of 100 Trials. It's reasonable to assume that Dark Atomic Boo would have been a more powerful version of Atomic Boo.
 * The idea of a Big Boo being made of many Boos may have come from Boolossus in Luigi's Mansion.
 * While Boolossus is made from fifteen Boos, the Atomic Boo from Paper Mario: The Thousand-Year Door is still smaller than Boolossus, even though it's made from two hundred Boos.
 * Boolossus and Atomic Boo have the same attack by trying to squish the player in Luigi's Mansion and Paper Mario: The Thousand-Year Door, however the Atomic Boo in Super Paper Mario acted like a normal Boo.