Spiderdemon

The spiderdemon, called the spider mastermind in Depths of Doom Trilogy's manual, is the boss of the final episode of Doom, Inferno, and again of the final episode of The Ultimate Doom, Thy Flesh Consumed. It has 3000 hit points and is one of the toughest creatures in the game. The spiderdemon appears as a huge brain with facial features on it, mounted atop a cybernetic chassis with four mechanical legs and a chaingun, making it similar to a spider at first glance.

The Doom II game booklet humorously presents the spiderdemon as the mother of the arachnotrons: ''You guess the Arachnotrons had to come from somewhere. Hi, mom. She doesn't have a plasma gun, so thank heaven for small favors. Instead, she has a super-chaingun. Crap.''

The spiderdemon is not mentioned in the Doom game booklet, presumably to avoid a spoiler. Perhaps as a result of this, the game booklet for the Depths of Doom Trilogy erroneously states that it appears in Doom II only.

Combat characteristics
The huge chaingun on the spiderdemon's chasis fires three bullets with every shot, much like the shotgun guy's shotgun, but at a rapid rate of 425 shots per minute. When a spiderdemon begins firing, it will not stop until its target moves out of view or dies, or if it is stunned (where it will walk a bit immediately after the pain state) or killed. Similar behavior can be observed in the heavy weapon dude and the arachnotron.

Spiderdemons, like cyberdemons, are immune to all blast damage, taking only direct hit damage from hits. This means a greater number of rockets are required to kill them than might be expected.

E3M8 boss battle
She appears on the bottom right 'clover leaf' of the map with a Baron of Hell (on harder difficulty levels) in the top left leaf and two Cacodemons occupying the other corners of arena. Almost all ammo is on a raised walkway above the main arena containing mostly of rockets and a few cells (B), except for the Plasma rifle, which is in a small room in the center of the map (C). The only way to access the walkway is from a set of steps to the north of the central building, or by walking along the walkway upon entering the level. This lack of ammo provides extra challenge and you are vulnerable to the Spider's hitscan attacks. As there is barely any cover (except for the thin pillars of the circular room where the Plasma Rifle and Mega Armor is located), to protect yourself from the Spider's bullets, moving quickly is key to survival here. There are NO HEALTH RECOVERIES here, so make your health count!

An effective strategy for this level is to deliberately cause the other monsters present on the level to attack the Spider Mastermind. The Spider Mastermind will then become preoccupied battling with the other monsters and will ignore the player's fire until the attacking monsters are killed. For example, you can move behind a Cacodemon, and the Spider will try to fire at you, but will fight the Cacodemon instead. Fire at the Spider from behind the Cacodemon, but DON'T FIRE AT THE CACODEMON ITSELF! Eventually, the Spider will kill the Cacodemon, but the combined forces against the boss will cause it to die faster (see demo below). This method is a good way to distract the Spider in battle so you can collect the ammo that is sitting the outer ledge. As a consequence of the extra ammo and monster respawning of Nightmare skill, this is one of the few levels that is generally easier in Nightmare mode than Ultraviolence.

E4M8 boss battle
On hard skill levels, there will be a few Barons with her. You can use them to weaken/kill the Spider Mastermind. Near the Spider Mastermind is a hidden area with a BFG and some ammo. Check the walls while she's in a fight with an enemy so you don't risk being killed.

General tactics
When fighting a spiderdemon, it is essential to keep one's distance as much as possible; even at medium range, the monster's attack can be devastating. Using the more powerful weapons is recommended against it, although since the spiderdemon has a low pain chance, rapid-fire weapons will not completely prevent it from attacking. Using melee attacks against it is extremely dangerous, except in the rare cases where the spiderdemon is pinned by another attacker. In E3M8: Dis, it is possible to stand up on the ledge above ground level and stay at great distance from the monster. At this range, the spiderdemon's attack will not aim toward the player, and therefore never hit its target. Also, the spiderdemon is large and tall enough that, even while standing on the ledge, projectile attacks will reach it.

However, due to its large size, it will soak in most if not all BFG rays from a point blank shot, dying in only 1 or 2 hits. A skilled player can therefore kill it easily by running up to it and shooting it twice with the BFG before it can kill the player, making the boss fight in E3M8 extremely easy and fast if one has a BFG. Utilizing monster infighting can be effective when battling a spiderdemon. If one does not have the BFG, the Rocket launcher or the Plasma rifle are recommended.

Data



 * 1) This table assumes that all calls to P_Random for damage, pain chance, blood splats, and bullet dispersal are consecutive. In real play, this is never the case: counterattacks and AI pathfinding must be handled, and of course the map may contain additional moving monsters and other randomized phenomena (such as flickering lights). Any resulting errors are probably toward the single-shot average, as they introduce noise into the correlation between the indices of "consecutive" calls.
 * 2) The target must be close enough to compensate for the weapon's recoil.
 * 3) Assumes that direct hits are possible, which does not occur in any stock map.

Appearance statistics
In classic Doom, the spiderdemon is first encountered on these maps:

The IWADs contain the following numbers of spiderdemons:


 * 1) May be encountered earlier if the super secret level is played.