Doom Roguelike Enemy Analysis: Arachnotron

HP: 50

Protection: 2

Ranged Accuracy: +3

Melee Accuracy: +3

Ranged Damage: 1d5*5 Plasma

Melee Damage: 1d3 (+2) Melee

Speed: 130%

Inventory: Power Cell*20

Experience: 263

Danger: 9

Minimum floor: 13/10/7

Maximum floor: 50

Experience per Danger: 29.22

Has -100% melee damage resistance, thus taking doubled damage from (most) melee attacks.

Evasion: Base of 20%, +4% per tile of distance, making for a maximum of 52%

Attack chance: 60%

So while I talked in the Former Commando post about how Arachnotrons are not clearly more dangerous than Former Commandos, it should be emphasized that I don't mean 'Arachnotrons aren't dangerous'. They are absolutely very dangerous, with a collage of qualities that make it extremely difficult to ever render them entirely ignorable.

First of all is their above-average Speed; same as a pinkie Demon's but now attached to a ranged attacker, not to mention to an enemy who has standard vision instead of reduced vision. Arachnotrons are in fact one of the biggest reasons why I feel Tactical Boots are basically mandatory to Assemble, as well as an outsized contributor to Hellrunner being a good Trait: because higher movement speed is mandatory if you want to be able to actually run away from Arachnotrons (The movement boost from Running is not enough to open space on its own, certainly not if your Armor is slowing you down at all), drastically reduces the odds of walking into view of an Arachnotron and immediately being hit with two volleys, and of course makes you way more likely to Dodge their shots.

Notably, the above-average Speed means Arachnotrons are deceptively dangerous in melee. Nowhere near as dangerous as at range, mind, but if you compare them to an Imp, they hit just as hard per swipe... but are not only way more accurate but will also be getting in swipes noticeably more often. Among other points, when your defenses are solid Arachnotrons actually become more dangerous in melee than several enemies whose melee Accuracy and damage are higher than the Arachnotron's. (eg Lost Souls, or even Hell Knights if you have a very good defensive kit) After all, if you're knocking everybody down to 1 damage, at that point the Arachnotron striking more frequently gives it a big leg up.

Second is their high volley rate, exacerbated by their good Speed. If you look at the damage totals, a Baron of Hell is only a little bit behind an Arachnotron (Max damage is 20 for a Baron's acidball vs 25 for the Arachnotron's plasma volley), but it's possible to have a really solid defensive kit that knocks Baron volleys down to 1 damage apiece... while Arachnotrons do a minimum of 5 damage if every shot connects. And get turns to lob volleys 30% more often than Barons. And spend their turns on lobbing volleys 50% more often than Barons. So for something like a Berserking Marine with a couple points of Tough As Nails or the like, both enemies are knocked to minimum damage, but Arachnotrons will average something over five times the DPS of Barons of Hell!

Third is that they're comparatively resistant to the Dodge mechanic. If you don't have Tactical Boots and/or ranks in Hellrunner, bobbing and weaving expects to only waste about half their shots, which is unreliable in general but is especially unreliable given the game clearly rolls Dodge on each individual shot in a volley. By default, an Arachnotron shooting Doomguy expects to pretty reliably do some damage... and by default, a single point of damage is 2% of Doomguy's max HP. This adds up to death pretty quickly!

Furthermore, Dodge's weird mechanics mean their high Speed makes them even more resistant to Dodge than just their Dodge numbers suggest. If you take a step to the side, and then an Arachnotron takes two turns before you get your next turn, their second volley can't lose any shots to Dodges!

Notably, this somewhat ablates their vulnerability to Melee damage and poor performance in melee combat. If Arachnotrons were set up more like the fire/plasma/acidball-tossing enemies in their stat profile (But retaining that Melee weakness), it would be mostly-safe to zig-zag toward them to get in melee and Chainsaw them to death. As-is, they tend to wear Doomguy down pretty substantially if you try to do that, even if you've got a strong defensive kit: ideally you do things like lure them around corners to minimize opportunities for them to fire at all.

Fourth is the counterintuitive point that Arachnotrons doing poor damage per hit is actually to their advantage. The relatively obvious point is Berserker: if a Baron of Hell tosses an acidball into a Berserker Doomguy and ends up rolling max damage, they instead activate Berserker and do scratch damage. If an Arachnotron fires a volley and rolls for 25 damage... Berserker doesn't activate, and only other defenses apply. The more reliably relevant point, however, is actually that they can't apply knockback.

This is one of the key reasons why Arachnotron packs are one of the main things that can pop out of nowhere and kill Doomguy in one or two of Doomguy's turns. When a swarm of Barons of Hell or Revenants appears in the fog as Doomguy steps forward, generally the enemies don't get to do anything close to their hypothetical max damage, because one of them rolling a scary-high amount of damage is probably also knocking Doomguy back out of sight, preventing anybody else in the swarm from opening fire on Doomguy. When Doomguy steps into view of five Arachnotrons, he unavoidably gets peppered with 5-10 volleys, when each volley's base damage can potentially rip off half his base HP; high damage rolls don't knock him to safety, they kill him.

Incidentally, this is another way Dodge helps less against Arachnotrons than you might hope, as Dodge doesn't care why Doomguy's position is different from the last time his attacker got a turn, it just cares that his position is different. Sidestepping into view of a blob of Revenants and having the first one blast Doomguy even further to the side may leave him in view of the other Revenants but result in all the other Revenants wasting their time blasting the spot he was standing right before he moved into their view. Arachnotron groups can't possibly self-sabotage in this manner.

Fifth is of course that Arachnotrons are quite beefy. Not quite as beefy as a Baron of Hell, no, but 50 HP and 2 Protection is still a lot. There aren't very many ways to be deleting Arachnotron's in one action (Especially at range), and even taking them out in two actions is a pretty tall order. You tend to need to rely on corner-shooting and radar-shooting if you want to kill them without them getting in volleys, and they're tough enough and fast enough that it can be a struggle to kill them before they get in range one way or another.

Sixth is that their Plasma damage makes Arachnotrons even more unimpressed with Protection. This is honestly one of the smaller bits of Arachnotrons Being Deadly, but for example Green Armor does literally nothing to help Doomguy survive Arachnotron volleys (Unless coupled with a rank in Tough as Nails), and Red Armor isn't 'their shots can only do 1 damage' but instead is 'their shots do 1 damage 60% of the time, but 2 or 3 damage the other 40%'. It also is one of the top reasons why they're A Problem for Malicious Blades.

It's worth pointing out that Arachnotrons are one of the better enemies to keep in mind the option of simply clicking on a target to melee it even while equipped with a ranged weapon. Even just dipping 2-3 ranks in Brute and punching them is surprisingly viable; with Brute 3, Doomguy will hit about 98% of the time, and will do 18, 20, or 22 damage per punch, which is enough to kill an Arachnotron in three successful punches perfectly reliably. (If Berserking, you'll typically kill them in two punches) Even Brute 2 takes at most 4 successful punches! This is especially important to keep in mind with Shotgun builds, as it's almost impossible for Shotguns to not knockback enemies shot at point-blank, and shoving an Arachnotron out of melee of course means its damage potential goes way up if it survives... which it probably does. Only the Super Shotgun and Jackhammer are lethal enough that a point-blank shot might take an Arachnotron from full HP to dead in one pull of the trigger.

It's also worth pointing out that Arachnotrons tend to show up reasonably frequently once they enter rotation, and are in fact one of the bigger reasons why Plasma Cell weapons become more appealing late in a run: because Arachnotrons showing up ensures some Power Cells are around. That said, do keep in mind that they don't drop very many Power Cells, and are durable enough that Power Cell-using weapons tend to need multiple pulls of the trigger to kill them. For example, an unmodified Plasma Rifle fired with Son of a Bitch 2 and Triggerhappy 2 can kill an Arachnotron in one volley, but unless you're on Angel of Max Carnage, the usual outcome is you'll have to shoot again, at which point you've spent 16 Power Cells to kill an enemy that drops 20 Power Cells. As such, Arachnotrons being about isn't really enough to main Power Cell-using weapons, it's just a reason to use them supplementally.

Unless you're an Ammochain Marine, of course, in which case 2 pulls of the trigger is spending 2 ammo to get 20. Go right ahead with relying on your Plasma Rifle in that case.

Oh, and Arachnotrons are another enemy 0.9.9.8 gave a new graphic, that being the one on the right. I'm... not sure why it did this, as the old one worked fine and there's not really a benefit to the change that I can tell... but it did. For some reason.

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Next time, we get started on the dreaded VMR, starting with Revenants.

See you then.