King Boom Boo (Sonic X)

King Boom Boo (キングブーブ) is a character that appears in the Sonic X anime series and its comic series published by Archie Comics. He is a giant ghost who haunts an ancient castle on earth along with smaller Boos.

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

When a film studio were trying to shoot a movie including Lindsey Thorndyke at King Boom Boo's castle, the talisman keeping King Boom Boo and the Boos trapped in their own world was removed from its pedestal, allowing them to roam around in the castle. King Boom Boo and his minions then began kidnapping the people in the castle which included Lindsey and the people visiting the set, such as Ella, Tails, Cream, Cheese and Sonic, trapping them inside a space inside the walls.

When Chris and Amy came to find their friends with the talisman, King Boom Boo tricked Amy, by mimicking Sonic's voice, to use the talisman to let him fully enter the living world. Now free, King Boom Boo quickly caught an enraged Amy and had one of his minions possess her. However, Chris discovered a way to use the talisman to free his imprisoned friends, allowing Sonic to beat back King Boom Boo long enough to let them all escape. Enraged, King Boom Boo chased after the escapees, but was brought back to his world once more when Chris returned the talisman to its pedestal.

Archie Comics
After the incident at the castle, the talisman was stolen from the castle and taken to one of Lindsey Thorndyke's summer homes on an island. Summoned there by the talisman, along with the disturbance from his rest by the endless activity from a recently-built tennis court nearby, brought a great annoyance to King Boom Boo. His loyal horde of ghosts consequently possessed everyone on the island, including Cheese, Lindsey and Vanilla the Rabbit, with King Boom Boo planning to have his ghosts possess enough living people to enable him to enter the world of the living for good. Cream and Chris managed to reason with King Boom Boo that his time on Earth, and he conceded to retract his presence and his ghosts release their hosts, but extracted the promise of the talisman being returned to its proper place by dawn, which was done by Sonic. Linsey then planned to convert the tennis court into a garden to further ensure King Boom Boo's continued sleep.

Personality
Capable of coherent speech, King Boom Boo is a mischievous and deceiving ghost. However, he is reasonable and has a distinct sense of honor, as shown when he keeps his promise to Chris and Cream of releasing the people his minions had possessed though they had to fulfill his demands as well.