Heavy weapon dude

The Chaingunner (sometimes called Heavy weapon dude) is a new addition to Doom II. He carries a chaingun as his weapon, which he drops upon his death. The rate of fire by his chaingun slower than the speed of the player's chaingun, and the sound effect used is that of the shotgun. When a chaingunner fires, he doesn't stop until he kills his target, his target leaves his line of sight 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.