Boo
Boos are the ghosts in Super Mario games. They are shy creature; they hide and become invisible whenever Mario is facing them. In some games, boos take on a more active role. In Super Mario 64, Boo's Haunted Mansion was the 5th level. In Mario Tennis and Mario Golf, Boo was a playable character. In the Mario Party series, Boo originally would steal coins or stars from characters, but by the sixth installment Boo was a playable character.
As A Sticker
Boo appears as a sticker in Super Smash Bros. Brawl. He is in his Mario Tennis role, complete with a racket. When applied to a trophy in the Subspace Emissary, the sticker increases the damage done by thrown items. The sticker is extremely easy to get, as every time the sandbag is hit more than 900 ft. in the Home Run Contest.
