The Bullet Bill
The Bullet Bill is an item obtained by racers near or in last place. The item temporarily turns the racer into a Bullet Bill causing the racer to become invincible. The effects of the Bullet Bill makes the racer travel faster with no steering involved. Its speed exceeds even that of a Golden Mushroom.
With the Bullet Bill, you can still die when activating it after falling off the track.
The Bullet Bill will wear off once it passes a set number of racers, or a set amount of time (usually 7.5 seconds) has passed. It is the fastest power up.