The arachnotron is a spider-like monster from the game Doom II. It is supported by a metal chassis and its body consists primarily of a large brain, along with two small arms. Instead of a chaingun it wields a powerful plasma gun that fires bursts of yellow and green energy.
Arachnotrons were one of the two main constituents of Chuck the Freaking Alien's army from Hell. They were dispatched to apprehend Manfred von Richtofen and acquire the Heck Outta Here. This led to an attack on the Avatar Supreme Commander's base in Antarctica. CivGeneral and Co. had to fight their way out of the base, losing track of lord_joakim in the process.