Big Boo (Paper Mario series)

Big Boos, also known as Atomic Boos, are enemies that have appeared in the Paper Mario series.

Paper Mario: The Thousand-Year Door
Atomic Boos make their debut in Paper Mario: The Thousand-Year Door, with a single one appearing as an optional mini-boss. 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 agreed to be nice to the Boos, they swarm him as soon as they are free. If Mario knocks the Boos away twice with the Super Hammer by using the Spin Attack, the Boos combine together to make 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. Once Atomic Boo is defeated, he relinquishes his Lucky Start badge to Mario and the Boos stop their swarming and appear as normal enemies.

A graphic of a purple Atomic Boo variant was unused, but cannot be encountered. It is reasonable to assume that it would have been a more powerful version of Atomic Boo.

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. Multiple Atomic Boos occasionally appear in the Mansion Patrol minigame; though slower than regular Boos, Atomic Boos take several hits to defeat instead a single one, and defeating one gives many more points than defeating a regular Boo.

Paper Mario: Sticker Star
In Paper Mario Sticker Star, the enemy was renamed 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 has been put out will light up the candle once more. Note that 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.

Trivia

 * 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 is made from two hundred Boos.
 * The Atomic Boo bears a striking resemblance to Bigger Boo from Super Mario World 2: Yoshi's Island.
 * 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, respectively; however, the Atomic Boo in Super Paper Mario acts like a normal Boo.
 * It is possible for the Atomic Boo in Paper Mario: The Thousand-Year Door to drop the reward for defeating it, the Lucky Start badge, down the hole revealed by pushing the star statue. This renders the badge unobtainable unless the player restarts from a previous save.