Heavy weapon dude

The Chaingunner (sometimes called Heavy weapon dude) is a new addition in Doom II. He carries a chaingun as his weapon, which he drops upon his death. The rate of fire of his chaingun is slower than that of the player's chaingun. The sound effect used is the same as the shotgun, but repeated rapidly. When a chaingunner fires, he doesn't stop until he kills his target, his target leaves his line of sight, he is stunned (causing him to move) or he is killed. Similar behavior can be observed with the Spider Mastermind and Arachnotron.

In the instruction manual distributed with the game, he is called a Former Commando.

Internally the Doom source code gives the Chaingunner the type name MT_CHAINGUY. The sprites for the Chaingunner have the prefix CPOS.