1 definition by SeaCaptainDrake

Boo

A scary ghost creature in the Mushroom Kingdom. Mario faces these a lot. These pearly-white ghosts will become invisible if anyone faces them. They usually cannot be disposed of. There are also other Boos, like the Big Boo, King Boo, and more.

"I thought I heard a Boo, but I turned around and saw nothing."

by SeaCaptainDrake December 6, 2003