Plasma Pistol

The Type-25 Directed Energy Pistol is a Covenant infantry firearm, carried commonly by the smaller species, such as the Unggoy, Kig-Yar, and the Yanme'e, as well as sidearms for the larger species such as the Sangheili and Jiralhanae.

Pictures
http://images3.wikia.nocookie.net/halo/images/thumb/5/57/Plasmapistol.jpg/300px-Plasmapistol.jpg