Bullet Bills (キラー) are bullet-like enemies in the Mario series that are shot from large cannons called Bill Blasters (キラー砲台).
A Bullet Bill is a large, black bullet-shaped enemy with angry eyes and white arms on either side of its body. It is generally fired from a Bill Blaster and usually follows a straight direction until it hits something or flies off-screen. However, some Bullet Bills are capable of homing in on Mario or Luigi like a missile, including a stronger, red variant known as a Bull's-Eye Bill, though regular Bullet Bills are often capable of this as well. In several games, Bullet Bills explode upon making contact with the player or a surface, and the explosion is capable of destroying certain objects. Bullet Bills are also immune to certain attacks such as fireballs from a Fire Flower, though they can generally be defeated upon being jumped on.
In Super Smash Flash 2
As an Assist Trophy
A Bullet Bill and a Bill Blaster in Super Smash Flash 2.
Bullet Bulls appear as an Assist Trophy in Super Smash Flash 2. When summoned, a Bill Blaster will appear on the ground, with its top acting as a platform. After a short time passes, the Bill Blaster will launch a Bullet Bill, which travels moderately slowly and homes in on the nearest opponent. After a Bullet Bill hits an opponent or reaches the blast line, the Bill Blaster will launch another Bullet Bill. The Bullet Bills can be launched from either side of the Bill Blaster, and a total of six Bullet Bills will be fired before the Bill Blaster disappears. Each Bullet Bill deals 13% damage and moderate knockback upon hitting an opponent. Additionally, dealing flame damage to a Bullet Bill will cause it to become red like a Bull's-Eye Bill, though its behavior does not change.
As an enemy
This article contains information of a formerly confirmed feature.
The original source that confirmed the subject has otherwise become obsolete, outdated or deprecated and has yet to be re-confirmed by an official modern source.
Bullet Bills were originally confirmed by the Smash Flash DOJO!!! to be an enemy in Adventure mode. It would appear on Mushroom Kingdom on Hard and Insane difficulties and travel forward to attack the player. A homing variant of the Bullet Bill with red eyes was also shown. However, with the DOJO!! now being outdated, the current status of Adventure mode, as well as Bullet Bill as an enemy, is unknown.