King Boom Boo

King Boom Boo is a giant ghost creature that appears as a boss in the video game Sonic Adventure 2. Appearing as a huge white blob with short arms, googly eyes and a wide, blue-lipped mouth with a rainbow-coloured tongue, King Boom Boo rules over the many Boos and Boom Boos that haunt Doctor Eggman's pyramid base.

Sonic Adventure 2
After clearing the Death Chamber stage, Knuckles the Echidna encounters King Boom Boo in a centralized chamber. The great ghost attacks by chasing Knuckles around the pillar in the middle of the chamber, throwing blue fireballs and breathing great waves of spectral flame. Following King Boom Boo is a Boo carrying an hourglass. Knuckles must run around the pillar when King Boom Boo breathes fire and attack the small Boo, flipping the hourglass. When the hourglass flips, doors in the ceiling open and sunlight floods the chamber. King Boom Boo hates sunlight and will phase into the floor and walls, appearing as a shadow. Knuckles can follow the shadow and dig in its location, causing King Boom Boo to emerge. The monstrous ghost is smaller than he first appeared and vulnerable to Knuckles' punches, so Knuckles can run after him and hit him. After being hit once, King Boom Boo will speed up and flee at a much faster pace, though it is still possible for Knuckles to hit him again before the ceiling closes, providing he chases the ghost by running adjacent to the pillar in the middle of the room. After the ceiling doors shut, the sunlight is gone and King Boom Boo will repeat his original attack pattern. It takes four hits to defeat him.

Sonic X
King Boom Boo also appears once in the Sonic X anime series. In the episode "Sonic's Scream Test", Chris Thorndyke's mother Lindsey is starring in a movie that is being shot in a haunted castle. During filming, an ancient talisman was removed from its pedestal, which allowed King Boom Boo and his Boos to enter the mortal world. 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 in a space inside the walls.undefinedWhen 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.