The Wario Bomb is the logo for Wario 's softwhere Company, Wario Ware.
Its also on the back of his Biker Jacket he wairs in Super Smash Bros. Brawl and the WarioWare games.
In the WarioWare games, it is used as a timer to show how much time is left to complete the current microgame. The fuse on the bomb is lit and slowly burns out. When The lit fuse reaches the bomb, the microgame is over.