Boom

Boom (ブー) is a character that appears in the Sonic X anime series and its comic series published by Archie Comics. They are a breed of ghosts who haunt an abandoned castle on Earth and the minions of King Boom Boo.

Appearance
Booms have small and round white bodies. Calm Boos have black, soulless eyes, knitted up mouths, small thin hands, and two small sharp points on their bottom which resemble legs. When hostile, Booms gain red and orange maniac eyes with black pupils, sharper hands with three pointy fingers and the ends on their bottom merge into one. Their mouths are also opened, revealing sharp black teeth.

Anime
The details of the Booms' background and how they and King Boom Boo came to be are unclear, though it is implied to be tied to a legendary subject (in the English dub, it is hinted they originate from an ancient burial ground that their castle was build upon and that they were behind the disappearance of the castle's original owner).

When a film studio was shooting a movie starring Lindsey Thorndyke at their castle, the Booms were awoken when the talisman keeping them sealed in their world was removed from its pedestal. During the following nights, Booms would kidnap visitors in the castle and drag them into a space between the walls, including the film's staff, Lindsey, Cream, Cheese and Ella, despite Amy, Tails and Chris' attempts to save their friends. As Sonic came to the rescue during one such attack, the Booms kidnapped him and Tails too, though Sonic managed to give the talisman to Chris.

The Booms later attacked Amy and Chris when they looked for their friends, but got scared away by the talisman. Following the Booms to a room, King Boom Boo tricked Amy into releasing him into the living world. A Boom then possessed Amy and had her chase Chris for their own amusement until Chris used the talisman to free the ghosts' captives, and Sonic got the Boom out of Amy. The Booms tried fighting back, but were easily defeated by the heroes, who escaped the castle and resealed the Booms once Chris returned the talisman to its pedestal.

Archie Comics
After the incident at the castle, the Booms and King Boom Boo were summoned to the island of one of Lindsey Thorndyke's summer homes when the talisman from the castle was brought there. When King Boom Boo could not sleep in his own world due to the noise from the surroundings, he sent out his Booms to possess enough people for him to enter the living world. When only Chris, Cream and Cheese were left, the Booms pursued them relentlessly until most of them were summoned to serve their king. Some Booms still hunted the heroes, and even got Cheese, until Chris and Cream made a deal with King Boom Boo. In exchange for the talisman being returned to its pedestal by dawn, the Booms and their leader willingly released their victims and returned to their world.

Personality
Similar to their king, the Booms are mischievous and malicious, giggling and laughing whenever they cause misdeeds. They ferociously possesses people and attacks them quickly and unexpectedly.

Powers and abilities
Being ghosts, the Booms possess a number of supernatural powers. They are capable of levitation, can render themselves and those they touch intangible, and turn invisible. They can also stretch their arms like cloth and merge together to form bigger and stronger ghosts. More mysterious powers they wield include manipulation of mass, like completely repairing a shattered stone wall, and altering mirror images.

Booms can possess their victims by phasing into their bodies, allowing them to take full control of their body and abilities (like Amy's usage of the Piko Piko Hammer). In addition, they retain their levitation skill. As a side-effect, the victim takes on the Boom's facial characteristics.

Unlike King Boom Boo, the Booms are able to freely travel between their world and the living world (when not constricted by the Talisman). They also share a connection to their leader that lets them empower him; the more living people they possess, the stronger King Boom Boo's bridge to the living world becomes, eventually reaching the point where he can cross over on his own.

Weakness
All Booms are naturally scared of the talisman used to sealed in their castle―just the sight of it is enough to sent them fleeing. When not relying on trickery, the Booms are actually physically weak opponents which can be incapacitated with minimal force. Also, knocking out their possessed victims can make a Boom leave their body.