

The Spider Mastermind is not mentioned in the Doom manual, presumably to avoid a spoiler. The Spider Mastermind has 3000 HP and is one of the toughest monsters in the game. It was responsible for the deaths of many scientists.

According to the game's epilogue, the Spiderdemon masterminded a demonic invasion of a moon base on the Phobos moon. The Doomguy encounters the Spiderdemon only at the final level. In the first game, the Spider Mastermind is referred to as the Spiderdemon. In Doom (2016) Spider Mastermind's design is similar to its classin incarnation, with the added refinement and stylizing in design. Its brain is splattered on impact, the monster then emits a feral grunt that is readily cut out by an explosion, and all that remains are its shattered robotic legs and dismembered facial features in a huge pool of blood. A soft, whirring-down sound (similar to a mechanical rotor cooling down and stopping spinning) is heard as the body falls sideways to the ground, engulfed in flames. When killed, the Spiderdemon's mechanical body shuts down and collapses. Similar behavior can be observed in Arachnotron.

When a Spider Mastermind begins firing, it will not stop until its target moves out of view or is dead, or the monster itself is stunned or killed. The huge chain gun on the Spider Mastermind's chassis fires three bullets with every shot, much like the Shotgun Guy's shotgun, but at a rapid rate of 467 shots per minute. A Spiderdemon emits a demonic roar mixed with loud, whirring machinery which starts low-pitched but progressively "grows" in a crescendo to a high-pitched tone once activated. When the Spider Mastermind dies, it's brain explodes into chunks of flesh and it's mechanical legs tip over. Two small arms are also connected to the base.Ī chain gun is located directly in the base's center. Four large, mechanical legs are connected to a base on the body. It has red eyes and a big mouth with fangs. The Spider Mastermind appears as a large brain with many other physical attributes.
