Bullet Bills are enemies that appear in Super Mario Galaxy, New Super Mario Bros. Wii, Super Mario Galaxy 2, Super Paper Mario, Mario Party 8, Mario Party 9, Super Smash Bros. Brawl, Mario Super Sluggers, Mario Strikers Charged Football, and Mario Kart Wii. They are bullet-like enemies with with arms and angry eyes. Their behind lets out smoke, much like a real bullet. In Super Mario Galaxy, Bullet Bills appear as enemies. They are fired from Bill Blasters that greatly resemble Cannons. These enemies fire in a straight line, however, when Mario/Luigi stands near a Bill Blaster and it fires a Bullet Bill, or if he gets near a Bullet Bill, its eyes will turn red and it homes in on him. The Bullet Bill will continue to chase the heroes until it hits them, an obstacle, or an enemy. They can catch up to the heroes if they are running from them with ease, however, they aren't fast enough to hit them if they continue to run from them. Since Bullet Bills home in on the heroes, they can be used to destroy cages and break fences. A gigantic robot that fires Bullet Bills named Megaleg can be defeated by doing so. However, if a Bullet Bill hits Mario/Luigi, it will explode. Mario or Luigi will be knocked down for a couple seconds as well as lose a wedge of health from their Health Meter. Bullet Bills are one of the most common enemies in Super Mario Galaxy; they make many appearances in certain galaxies. Torpedo Teds, a sub-species appear in the Buoy Base Galaxy. They behave just like Bullet Bills by homing in on Mario/Luigi, however they make a radar sound which gets faster as they get closer to the heroes. Banzai Bills, a large sub-species of Bullet Bills, appear in Bowser's Galaxy Reactor and they are shot from Banzai Bill Blasters. These sub-species of Bullet Bills do not home in on Mario. Bullet Bills in Super Mario Galaxy can only be defeated if they collide into something. If one is chasing the player at a bad time, they can simply get it to crash into a wall, enemy, obstacle, etc (as long as it is not the player himself). In New Super Mario Bros. Wii, Bullet Bills reappear as common enemies that a fired from Bill Blasters. They first appear in World 3. They play an important role in World 6 as the world's Enemy Course enemies. Bullet Bills also appear in several levels of World 7. In World 5-5, Bullet Bills are fired from somewhere off-screen instead of from Bill Blasters. Banzai Bills also reappear in New Super Mario Bros. Wii. A new sub-species of Bullet Bills, the King Bill appears as a large indestructible enemy, that is so large, that it takes up slightly more than half of the screen if you measure it vertically, not horizontally. These enemies are way bigger than Banzai Bills. King Bills only appear in World 9-8, which is really the final level of NSMB Wii. Missile Bills, and a new sub-species of Banzai Bills, Missile Banzai Bills, appear in World 9-3. Bullet Bills are still fireproof, meaning a Fireball from Fire Mario (or Fire Luigi, Fire Blue Toad, Fire Yellow Toad) cannot take them out. However, they can be frozen from an iceball from Ice Mario (or Ice Luigi, Ice Blue Toad, Ice Yellow Toad) after obtaining an Ice Flower, or from Penguin Mario (Penguin Luigi, Penguin Blue Toad, Penguin Yellow Toad) after obtaining the Penguin Suit. Unlike other frozen enemies, frozen Bullet Bills can be picked up and thrown. Destroying a frozen Bullet Bill's Ice Block, as well as stomping on them or touching them while under the effects of the Starman will defeat a Bullet Bill. Stomping on a Banzai Bill, Missile Bill or Missile Banzai Bill will also take them out. In Super Mario Galaxy 2, Bullet Bills reappear. Most of them have still having their ability to home in on Mario/Luigi, however, some in Bowser Jr.'s Fearsome Fleet or Bowser's Galaxy Generator fly in a straight line and do not home in on them. In certain galaxies, Yoshi can use his tongue to grab a Bullet Bill and place it in his mouth. However, the Bullet Bill cannot be swallowed. It can be spat out to send it flying the direction Yoshi and Mario/Luigi is facing, making it a very helpful feature when it comes to defeating enemies such as Undergrunt Gunners. This plays an important role in the boss battle with Megahammer in Bowser Jr.'s Fearsome Fleet, for Yoshi (Mario/Luigi will ride Yoshi) must capture the Bullet Bills he fires at him and spit them out at the large, bright blue orbs on his body. This must be done a total of eight times to defeat Megahammer and earn the Power Star that is released afterwards. Banzail Bills also reappear in SMG 2, however, Torpedo Teds do not. In Super Paper Mario, Bullet Bills only appear once in The Bitlands at Bowser's Castle. They can be taken out with a simple stomp on them. The player can also use Thoreau, a type of Pixl, to pick up the Bullet Bill and fire it at its Bill Blaster. In Mario Party 8, Bullet Bills appear in the mini-game Cardiators. Three Bullet Bills appear on a card as an enemy and subtract 9 (-9) in the player's HP. The Bullet Candy, which only appears in Bowser's Warped Orbit, transforms the player's bottom half into the end of a Bullet Bill, allowing them to hit three Dice Blocks (similar to that of the Thrice Candy), and lets them steal one star from each opponent they hit. Bullet Bills also appear in the mini-games Sick and Twisted and Thrash 'n' Crash as obstacles that must be avoided. If they are not avoided, then the player will die automatically. The mini-game, Superstar Showdown, uses Bullet Bills as projectiles fired from Bowser's cannon. Also, there is a helicopter that resembles a Bullet Bill in the mini-game Gun the Runner; it holds the three players trying to eliminate the solo player. In Mario Party 9, Bullet Bills appear in the mini-game, Billistics, whose name is a pun on "Bullet Bill" and "ballistics". This mini-game involves players dodging many Bullet Bills. Players also pilot Bullet Bills along the path in the mini-game, Speeding Bullets. In Super Smash Bros. Brawl, Bullet Bills appear as enemies in The Subspace Emissary, however, they do not appear in many levels. They do appear in The Jungle and The Swamp, for we can tell you that. All these enemies do is fly in a straight line. Their size has been increased, however, these enemies are still fairly weak. Even though they cannot be stomped on, they can be taken out with a few attacks or a smash attack. In a cutscene, silver Bullet Bills were fired at Donkey Kong and Diddy Kong, which explode after being attacked by Diddy Kong's attacks. Some Bullet Bills home in on the player and they can be temporarily deflected. A Bullet Bill also has its own Trophy in Brawl, however, one must capture it with a Trophy Stand first. This can be fairly challenging since Bullet Bills are constantly moving. It is a little easier to capture one that is homing in on the player. Bullet Bills can be captured even when the Difficulty is set to intense, for they have low health. Bullet Bills also make an appearance in Mario Super Sluggers. Bowser uses them as his pitching special. Also, a Bullet Bill makes an important, yet small cameo in the ending movie. When Mario and Donkey Kong are blasting Bob-ombs out of Mario Stadium, Wario and Waluigi stuff a Bullet Bill into the Bob-omb Cannon. Mario, too frightened to even move, watches in fear as the Bullet Bill blasts toward him. Suddenly, Bowser appears out of nowhere and smashes it back to Wario and Waluigi, blasting them into the air. Bullet Bills may also pop up and fly around the outfield of Bowser Jr.'s Playroom, stunning players. In Mario Kart Wii, Bullet Bills are one of the many items that can be used. If it is used, the player's Kart/Bike becomes a Bullet Bill that moves at BREAKNECK SPEED. They will have bad turning, however, the good news is that players who are using this item can knock over any enemies, opponents or projectiles in their way. There is a limited time when the item is being used, however, it lasts longer depending on the position the player is in. This item can only be received when the player is in 8th-12th place. Bullet Bills in use can knock over players who are using the Mega Mushroom, but it cannot affect players who are under the effects of Star. Also, much like how there is a Kart that resembles a Blooper and a bike that resembles a Magikoopa, there is a bike known as the Bullet Bike that greatly resembles a Bullet Bill. It can travel very fast, making most of its other stats quite poor. This Bike can only be used by small characters such as Baby Mario and Dry Bones. Bullet Bills also make a short appearance in Mario Strikers Charged Football. It appears as the Skillshot of Shy Guy, which is known as Bullet Bill Blast. After fully charging the Football, which is really a soccer ball, Shy Guy summons a Bullet Bill, who he rides on. He rides on the Bullet Bill towards the Goalkeeper trying to knock him out in an explosion for a score.
Bullet Bill's Trophy from SSBBA shell fired from a special cannon known as a Bullet Blaster. Easily identified by their angry eyes, Bullet Bills fly across the land in perfectly straight lines. Though they easily shrug off fireballs, they can be stopped by jumping on them. A unique characteristic of the cannons is that they will not fire a Bullet Bill if Mario is standing right beside one.
- In Super Smash Bros. Brawl, the Bullet Bill's trophy states that "Bullet Bills fly across the land in a perfectly straight line". This is not true, for some Bullet Bills travel freely all over the place and others home in on players. Some also stay in place, like in the Paper Mario series.