Crown (King Boo)

King Boo's Crown is a piece of jewelry worn by King Boo that symbolizes his status as a king. It has changed in appearance throughout the various Mario games it has appeared in. Its first and most notable appearance is in Luigi's Mansion, where the crown possesses a dark diamond at the top. At the end of the game, when King Boo is defeated, he leaves his crown behind. Luigi gets to keep the crown, and with its help is able to build a new mansion that does not contain any Boos. Incidentally, the crown is worth the same amount as a single coin.

Officially, King Boo's crown also counts as a Red Diamond.