Arachnotron/Doom 64

In Doom 64 their physicality is considerably altered; the mechanical body is much bigger, with the brain head ducked down inside the machine itself instead of sitting atop it, also not having any organic arms like the classic version, and the mechanical legs (now six instead of only four) being longer and bent at upwards-pointing acute angles. Instead of a single plasma gun, the Doom 64 Arachnotrons possess two guns that fire out two blue plasma bolt shots simultaneously, but done so in spurts of five instead of a constant rate of fire, though it will continue firing as long as it can see the player. They first appear in MAP14: Eye of the Storm unless the player goes through MAP30: The Lair and MAP32: Hectic, which contain Arachnotrons but chronologically come first.