Monster Analysis: Phase Spider

Thanks to captaincaboodle for the Phase Spider piece, and to @TriaElf9 for Content Warning Nott!

  • Encounter Appearance: 2-10 Waste and Webs
  • Armor Class 13
  • Speed 30 ft, 30 ft climbing
    • Not impeded by webbing
  • Bonus action to enter Ethereal or Material Plane
  • Darkvision 60 ft, Passive 10
  • Suggested Average, Max HP: 32, 55
  • 74 damage taken, 3 HDYWTDT by Mollymauk

Phase spiders first made their appearance in Critical Role in Vasselheim in the previous campaign. Fortunately, unlike the highly-populated colony Vox Machina battled through, the significantly weaker Mighty Nein only had to hunt down a single matriarch. (Though if it had a mate that helped it produce its babies, we may never know…) The spider made its home in Zadash’s sewers, feeding on whatever humanoids or rats were foolish enough to get close enough for it to strike. Halls lined with webbing and drained corpses warned that this monstrosity had been settled for a while, and was very good at hunting.

With the exception of the modified HP total that we’ve come to anticipate, the phase spider’s stats appear to be pulled straight out of the Monster Manual (p334). Its evasive bonus action ability allowed it to travel back and forth between the Ethereal and Material Planes, making it appear invisible when it was simply vanishing with a different perspective on the party. This feature allowed it a surprise strike against Fjord without him or Nott perceiving its presence (even though it probably could have managed to do so without using the Ethereal Plane to travel). Its decision to disappear again during the first full round left the party with tied hands as they waited for it to return, and many of them were unable to act even when it reappeared due to distance.

Its +4 attack modifier and DC 11 poison bite was capable of dealing an average of 25 piercing and poison damage in a single attack. In two bites, Fjord took a total of 15 piercing and 20 poison damage, failing the second of two constitution saves. His Relentless Endurance brought him to 1, cutting off any potential paralyzing effect of the spider’s venom.

When the spider struck at Yasha, Mollymauk’s amplified blood maledict blinded the spider at the negligible cost of his own health. This not only prevented a crit from striking the barbarian, but also saved Jester from a bite entirely as she granted healing to Fjord in the following round. Nott and Caleb stayed a safe distance back from the fight, with Nott pouring in damage from her sneak attack and Fury of the Small and Caleb going full defense with Blur in the first round. Beau may have had trouble getting in range of the spider for the majority of the fight, but her broomstick gamble at the end of the fight brought the spider just in range to die to Molly’s mocking tongue.