The Phazer is a strange powerful laser pistol. Its origin is unknown. It may only be acquired in a special encounter in Fallout 2, which is a shuttle crash around three corpses dressed in a red uniform. It's a reference to the Star Trek weapon.
Phazers are directed-energy weapons, often in the guise of a pistol or rifle. In this case, it is in the shape of a small energy pistol. A phazer is a formidable handgun, which is evident in comparison to the common Wattz 1000 laser pistol.