Bullet Bill

Bullet Bills are a bullet-like enemies in the Mario series that are shot from tall cannons called Bill Blasters. A Bullet Bill usually follows a straight direction until it hits something or flies offscreen. A stronger variant, known as the Heat-Seeking Bullet Bill, moves slower, but homes in on the player. In the original games it is completely red, but in SSF2 it is differentiated only by its red eyes.

In Super Smash Flash 2
Buller Bill was originally confirmed by the DOJO!!! as an enemy in adventure mode. However, due to numerous inaccuracies and outdated information on the Dojo site, its current confirmation status is unknown.