The Peacekeeper stasis gun is a specialized pistol designed to stun and incapacitate rather than kill a living target. In their search for an intellant virus, Captain Larraq's squad was equipped with a stasis gun to use on any host that the virus occupied. It is likely that the gun was used on the virus' last host captured before the squad boarded Moya. It was later used on the Hynerian Rygel when it was believed the virus had infected him.
The stasis gun has a very slow rate of fire, taking several microts to recharge between shots.
(1.19 "A Bug's Life")