Boolossus

Boolossus, the Jumbo Ghost, is an enormous Boo and one of the portrait ghosts in the game Luigi's Mansion. This ghost is composed of fifteen regular Boos who can combine to create Boolossus. Although these Boos are normally timid and shy, when they form into Boolossus, all their fears disappear. The Boo is a servant of King Boo, leader of the Boos, and is the guardian of the third area of Luigi's Mansion. Its name is a pun on the words "Boo" and "colossus" and literally translates to "Giant Boo". Unlike other Boos, Boolossus has glowing yellow eyes.