Bumper (Super Smash Bros.)
From the Super Mario Wiki
A Bumper is an item in Super Smash Bros. and Super Smash Bros. Brawl. In Super Smash Bros, it remains on the ground when thrown, damaging players who bump into it. There is also a Bumper floating above the Princess Peach's Castle stage. For unknown reasons, the Flipper took its place in Super Smash Bros. Melee. In Super Smash Bros. Brawl, the Bumper reappears. Bumpers in this game can float in midair when thrown, making it possible to use them as deterrents for opponents trying to recover. Bumpers can also lie on the surface if thrown downward toward the ground.
In Super Smash Bros., if one is thrown and directly hits an opponent, it causes a significant amount of knockback despite causing only one percent of damage. In Brawl, no damage is done, but the knockback is even greater. Additionally, the knockback that the Bumper delivers increases as the target's damage increases.
 Trophy Information from Super Smash Bros. Brawl