Big Boo

Big Boo (also known in PAL versions as Atomic Boo) is a boss in Super Mario Galaxy 3.

Attack Method
Big Boo throws Bomb Boos at Mario, who must throw them back at Big Boo. He will be damaged, and will bounce around, hoping to crush Mario.

He has two Mimic tricks. One is to turn into Mario, who will copy Mario's moves, hoping to confuse players, and his second one is to mimic Professor E. Gadd, and as Mario approaches, Big Boo will emerge, damaging Mario.

Trivia

 * Big Boo's eyes resemble one of the players from the KISS rock band.