Bumper

Bumpers are bouncy obstacles introduced in the 1.30 update for Super Mario Maker. They can be created by shaking a Grinder. Touching a Bumper will cause Mario to bounce off it. The effects are similar to that of a Springboard or a Note Block, except Mario will bounce off it no matter which side he touches.

When bouncing off the top of a Bumper, the player can hold down the jump button in order to gain extra height. This is in contrast to a Springboard or Note Block, which both require the player to time the press of the jump button for the boost.

One unique property of Bumpers is that they allow all non-Mario entities to pass through them. For this reason they can be useful for creating a barrier or platform that only Mario may not pass.

Trivia

 * The Bumper is more likely to be based off the item from the Super Smash Bros. series with the same name.
 * The design of a Bumper is very similar to the rubber ball that Lemmy Koopa bounces atop in his most recent appearances, as they both have a yellow base with orange stars printed on them.
 * According to the director of the game, Yosuke Oshino, the development team added this item to further expand the jump mechanics of the game. "We hope that players will create thrilling, maybe even nail-biting courses filled with jumps. Having said that though, players are free to find their own uses for it. It may be a simple item, but it holds an infinite number of possibilities, and we’re hoping players will again find uses for it that we never imagined."