Chaingun (3.5e Equipment)
From D&D Wiki
This massive hulking metal gun is held in both hands due to weight, size, and sheer recoil. The sound of battle is washed out by the din of thousands of bullets streaking forth.The chaingun is powered by an air Djinn.
The chaingun is a very powerful weapon, but incredibly bulky. All attacks made with it take a -2 penalty. It takes a full round to 'warm up' and spin, to which one can make either normal or full round bursts to the targets. On any round which the gun is not being fired, it'll wind down and need another round to wind back up.
Besides normal attacks, as a full attack action you can sweep the chaingun in an arc, striking all targets in a 30 ft. cone once, with a Reflex save to half. The DC is your attack modifier.