The Bumper is a throwable round knob that bares a yellow Super Smash Bros. symbol on its top, with a bouncing blue ring at the bottom. After being thrown, the Bumper will create an additional obstacle on the stage and, depending where it was launched, it may remain airborne or stick on the floor. Anything that collides with the Bumper after being set will trigger the bouncing ring and will bounce off it. Depending on how the set Bumper was approached, it may bounce back the character at multiple different angles. For example, approaching the Bumper with an aerial attack may propel back the player a considerable distance that approaching it by simply jumping on it. Because the Bumper causes no damage nor flinching, unlike how it does in the Smash Bros. games, players may use it for their advantage and perform a surprise approach on unsuspecting opponents. However, due to the unpredictable bouncing nature of the Bumper, this may not be a convenient technique and can be more of a nuisance rather than being helpful. SSF2 notably features both the Bumper and the Flipper in the same game, after they were items that replaced each other in the official Smash Bros. games.
As noted by its description in the item switch, the Bumper originates from real-life bumpers from pinball machines as opposed to an actual video game entry. Bumpers serves as obstacles that actively push the ball away. They are operated by a switch connected to a ring surrounding the bottom circumference of the bumper that is suspended several millimeters above the playfield surface. When the ball rolls over this ring and forces one side of it down, a switch is closed that activates the bumper's solenoid. This pulls down a tapered ring surrounding the central post of the bumper that pushes downward and outward on the ball, propelling it away in the same way the item does for SSF2.