Banzai Bills are enemies in the Mario series. They are gigantic versions of Bullet Bills, and will shoot straight toward the player. They are jet-black and they smile angrily like a shark. Their first game appearance was Super Mario World, where the only way to get past them was to either jump on them and kill them, or slide under a hole. They disappeared for a long while, not appearing again properly until Super Princess Peach
Super Mario World
Super Princess Peach
His next proper appearance was in Super Princess Peach
New Super Mario Bros.
In New Super Mario Bros., Banzai Bills would shoot out of a cannon, and Mario/Luigi would then have to either jump on his head, or if Mario/Luigi had a Mega Mushroom, just run into him. Also, in the game Super Smash Bros. Melee, Banzai Bill would appear on Princess Peach's Castle, and would crash into the stage, it was also a trophy in the game as well. In Super Mario Galaxy, Banzai Bills would launched from a canon in the stage Bowser's Galaxy Reactor. Banzai Bills are also very big and very mean-looking.
In Mario & Luigi: Bowser's Inside Story, Banzai Bill appeared as a weapon instead of being an enemy. When Bowser finds three of his friendly minions in Dimble Wood. All they found was a blaster cannon that launches Banzai Bill, but they haven't found Banzai Bill. Bowser was very angry and he insulted his minions by saying idiot. His minions was scared and they will try to find the Banzai Bill. Mario/Luigi and their sidekick told him to find Banzai Bill instead of waiting for his minions. Bowser found him in Wiggler's garden farm where the crops are. He found him in the underground that got jammed by giga-carrot. Bowser thought giga-carrot would work, but it is very huge for the blaster and it is very weak. When he was arguing for that carrot, Wiggler came out of his home and he found Bowser. He said that he has Banzai Bill. In order to get the weapon, Bowser must finish eating the giga-carrot within 1 minute. The people in his body heard him and they went to the Bowser's stomach called Gut Check. To finish eating the carrot, the bros. need to pay attention to their sidekick. Their sidekick told them by breaking up the broken carrot pieces. The ball-like object called enzyme must be hidden in the carrot. You can find it by looking at the small fireworks going above Bowser in the top screen. Red enzyme digest all carrots at once, while yellow enzyme shrinks all carrots at once. Blue enzyme is very worse and it only shrinks some of them. If the Bowser fails to eat them, Wiggler will replace giga-carrot. If the Bowser wins, Wiggler will give him Banzai Bill. When Bowser eats the carrot, Wiggler was very angry and his segments turn red. He will also challenge Bowser. In this game, he has 540 HP. Which was quite ironic, probably if Wiggler tries to fool him. When Bowser kills him, he has fun carrying the Banzai Bill. When he tries to exit the garden, he suffered stomach pain and saying "YOWCH!! OW OW!!". The bros. investigate what caused the serious pain. You go to the stomach and you'll fight evil Durmite who is trying to hurt him. When you defeat her, Bowser feels okay but his arms hurt. He also have ability to punch tough things that he can't by running at them and then punch immediately. He then launches him into the air. Banzai Bill can be seen in the sky, where he is charging angrily at the castle. Midbus and Bowser's brainwashed minions found him and they were lucky because they dodged him by making the castle fly, which made him aim at wrong direction.
Super Smash Bros. Melee
In Super Smash Bros. Melee, a Banzai Bill will occasionally appear on the Princess Peach's Castle stage. A trophy of Banzai Bill also appeared. The trophy incorrectly stated that Banzai Bill's first appearance was in Super Mario World.
"Bullet Bills are shot out of cannons and fly on straight paths. In great numbers they're a nightmare; while Mario can stop most with a single jump, the rare giant one is much tougher to avoid. In Super Smash Bros. Melee, all Bullet Bills are extra large. They burrow into Princess Peach's castle and then detonate with immense power."