The Blaster is a Standard special move in the Super Smash Bros. series that can be performed by Fox McCloud, Falco Lombardi, and Wolf O'Donnell. It's basically a weak gun that can rapidly be shot at opponents. Fox's Blaster will damage enemies 1%, while Falco's will do 2%. Neither are powerful enough to shoot the player off of the stage no matter how hurt he happens to be. Wolf's Blaster, on the other hand, is much more powerful but he has to reload it after each shot.
Prior to the Super Smash Bros. series, the Blaster never appeared in any video game. However, Fox and the Star Fox team did wield them in the Star Fox comic series released in through Nintendo Power. Fox mentions his Blaster in Star Fox Adventures, though he never actually used it. Star Fox Assault marks the first game where they use them outside of Smash.