For Bullet Bill's appearance as a common enemy, see Bullet Bill (enemy).
Bullet Bill is a transformation item in Super Smash Bros. for Nintendo 3DS and Wii U and Super Smash Bros. Ultimate. It allows the user to transform into the character of the same name to ram into opponents.
Instead of "throwing" the Bullet Bill, the user transforms into one and flies in a straight line in the direction that the the control stick was pointed toward. The Bullet Bill travels the length of Final Destination before reverting the character back to normal. The Bullet Bill deals 25% and high knockack upon contact with any opponent, and if it hits a solid surface it will produce an explosion that deals 30%, making its potential damage output to be 55%.
Because of its damage, the Bullet Bill item can KO as early as 80%, making it a reliable finisher, particularly against heavyweights, and is extremely accurate due to the ability to be angled from any position. In addition, due to the distance gained, it can be used for recovery as the user is not put in helplessness. However, due to its speed and distance, angling it off-stage or close to a blast zone will self-destruct the user. Most importantly, due to it being a projectile, fighters with reflectors can reflect the Bullet Bill in the opposite direction, requiring caution when using against such fighters.
When you try to throw this item, you'll instead transform into a Bullet Bill and fly in the direction you were throwing. Anyone in your path will be knocked away. Be careful, though, since you fly fast and can barely steer—not to mention that foes can deflect you. KO them, not yourself!
The Bullet Bill as an item comes from the Mario Kart series, and originates from Mario Kart DS. It allows the user to transform into a Bullet Bill, and race through the track at a fast speed automatically and knocking over any opponent in its path. Because of its properties, the Bullet Bill usually is gained by a racer who is behind in the race. The fact that the Bullet Bill can also be held is a reference to how items in Mario Kart can be held for strategic use.
The design of the Bullet Bill is based off its design from Mario Kart DS.