Jackals' unlimited Plasma Pistols
From Halopedia, the Halo wiki
The Unlimited Plasma Pistols is a trick that can be performed in the Halo 2 campaign level, Sacred Icon.
Walkthrough
Play the Sacred Icon level until you find your Kig-yar and Unggoy allies. Destroy the ports the Sentinels come out of so your allies are safe. Grab a Type-51 Carbine, if you haven't already got one, and trade it to a Kig-yar Soldier (make sure your other weapon is not a Type-25 Directed Energy Pistol or you won't be able to trade with him).
Then charge up the Type-25 Pistol he just gave you and launch it at his shield. If this is done the first time, the soldier will freeze. This will bring the shield down temporarily and he will drop the Type-51 Carbine and pull out another Type-25. You can do this over and over and the Kig-yar will pull out a new pistol every time.
