Doom Roguelike Enemy Analysis: Spider Mastermind (0.9.9.7/0.9.9.8)

HP: 260/290/340/410/500 (Base of 250, plus 10*difficulty number squared)

Protection: 2

Ranged Accuracy: +4

Melee Accuracy: +4

Ranged Damage: 1d6*6 Plasma

Melee Damage: 1d3 (+15) Melee

Speed: 150%

Inventory: None.

Experience: 0

Danger: N/A

Minimum floor: N/A

Maximum floor: N/A

Experience per Danger: N/A

Immune to knockback and damage from Acid and Lava on the floor.

Subject to a unique 'staggering' mechanic: if a single individual hit does 20 or more damage to the Spider Mastermind, she will be unable to attack for one turn, though she will still able to move. This effect stacks, where each hit landed that does 20+ damage adds another turn of not being allowed to attack in a row.

Shots are subject to a scattering mechanic, where the volley will rarely aim all six shots directly at Doomguy even if he's holding completely still.

Evasion: ??

Attack chance: ??

The final boss of the game, the Spider Mastermind is another boss you cannot encounter in Angel of 100/Archangel of 666; you will only ever encounter her in the City of Dis. (ie floor 24 of a standard run) I'm actually unsure why this is so; she's interestingly unique, unlike eg the Arena Master, and there's nothing about her design that has me going 'yeah, I see why you wouldn't want her randomly showing up on regular floors'. Was it meant to keep the standard run final boss feeling special? Was it felt it would be disproportionately dangerous to melee builds if allowed to generate in a regular floor, where melee-build Doomguy might have to weather the maximum possible number of shots due to not having terrain to use as cover on approach? I hope it's that last one; I really wish she could show up in these runs, but would understand if it's not allowed to because her presence would seriously harm the viability of melee builds in such runs.

In any event, this means I should discuss the City of Dis briefly.

Like the Phobos Anomaly and Tower of Babel before it, the City of Dis is a pretty fixed level. You specifically start on either the west side or east side of the map (Picked randomly), trapped inside a walled-off area with a Lever to pull that will open the way to the central arena the Spider Mastermind is hiding in. This area is a roughly oval-shaped area with a few small pillars scattered inside it, and that's... basically it. There's no other enemies on the floor, no items, nothing but you and the Spider Mastermind dueling each other. It's dead simple.

The Spider Mastermind herself is more interestingly unique. There's her odd 'stagger' mechanic, there's her unique footstep sound she plays every turn, and her AI is unique: the Doom Roguelike wiki has spent years described several enemies as having an 'avoids melee' AI flag, but the Spider Mastermind is the only enemy in the entire game where 'avoids melee' is a meaningfully accurate statement, where she will in fact step out of melee with Doomguy! I'm actually not sure I've ever been attacked by her in melee, in fact; she really doesn't like staying that close to Doomguy.

The stagger mechanic itself is unfortunately not communicated by the game at all. You might notice her spending multiple turns wandering around randomly and wonder about that in broad terms, but I'd be very surprised if anyone ever inferred the basic picture of this mechanic by just playing the game without ever looking at the wiki or Chaosforge forums or the like. Especially since she already prefers to stay out of melee, when melee attacks are one of the most reliable ways to cross the stagger threshold; how are you supposed to tell the difference between 'she stepped out of reach because she hates being in melee' and 'she stepped out of reach because the stagger mechanic has barred her from attacking you this turn'?

Speaking of poor communication, her in-game description imitates the classic Doom description about her having a 'super chaingun'... even though in Doom Roguelike she does Plasma damage, like Arachnotrons, not Bullet damage like a Chaingun. Exacerbating this is the visuals and audio, which align with the Chaingun visuals and audio, rather than using the plasma weapon audiovisual elements that Arachnotrons and Plasma Rifles use! I imagine there are players out there who picked up a Bulletproof Vest, got excited about its potential for protecting them from the Spider Mastermind, and were very confused when she shredded them right through their intense Bullet resistance.

I'm actually not sure how her bullet spray mechanic works. This is a rare case of the Doom Roguelike wiki not documenting a major and obvious feature at all, even though it does document the stagger mechanic and various other nearly-invisible mechanics. I just know her animation tends to spray 2-3 bullets off-course even if I hold still, and the rate at which I get hit seems to align roughly to these visuals. I suppose it's possible it's a bit of visual flair that has no mechanical meaning, but I'm a bit doubtful. It's too bad her shots are too weak to do damage to terrain, taking away one of the more obvious ways to test these mechanics...

... so too does the wiki not document her attack chance or Evasion rules, oddly. I'm pretty confident her attack chance is high from experience, and would guess it's at least 60%, and similarly Dodging isn't very effective against her, but I don't know the numbers.

Anyway, all that said, the Spider Mastermind... tends to be a bit of a formality? On paper, she's incredibly deadly, with an absurdly high Speed and able to do up 36 Plasma damage per turn she takes, and to be fair, it's genuinely easy to go down fast to her, but she's very susceptible to corner-shooting, is surprisingly frail (Her base HP is technically 25% greater than the Cyberdemon's, but eg on Ultraviolence it's only 14% higher, while she has only 2 Protection and so will be hit a lot harder by various sources than a Cyberdemon), and only rarely actually approaches her peak damage potential. Her stagger mechanic also means you may well kill her without her attacking more than once, further reducing her true threat level.

There's another reason for why she tends to be a formality, but I'll explain that more next post.

Brief aside: the Spider Mastermind has a unique corpse graphic, but you can't see it in-game!

Which is too bad. It's one of the more comprehensible and distinctive corpse graphics.

Also, the Spider Mastermind was, in 0.9.9.7, the only boss other than the Cyberdemon to have an ultra-massive sprite. In her case, she's basically large enough to cover 6 tiles; 2 tall, 3 wide! This is unfortunately another way her fight is easy to approach incorrectly early in learning Doom Roguelike, as her visual size does not correlate to her mechanical size. She's still in just one tile, matching to where the chaingun on her sprite sits. If you pay attention to the targeting feedback, you can figure this out pretty quickly, but I imagine there are players who tried shooting at the side parts of her sprite and died, unaware that their bullets going through her sprite was because those areas aren't really a part of her body.

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Next time, we cover a very special boss.

See you then.