Thousand Thieves

All-Around Vision — This monster can see in all directions simultaneously and therefore can't be flanked.

Swarm Mind — This monster doesn't have a single mind (typically because it's a swarm of smaller creatures), and is immune to mental effects that target only a specific number of creatures. It is still subject to mental effects that affect all creatures in an area.

Discorporate — When the swarm strider is reduced to 0 HP, their constituent creatures collapse, scattering on the ground under their space and each adjacent square. If even one of the creatures gets away, the swarm strider can eventually re-form over 1d10 days (potentially longer in areas where there are few invertebrates). The scattered invertebrates must be destroyed within 1 round to destroy the swarm strider permanently. The invertebrates have a collective pool of 55 HP, and the same AC, saves, immunities, resistances, and weaknesses as the swarm strider. The invertebrates can't take actions but they escape automatically once the round elapses. At the GM's discretion, clever means of trapping or eliminating the creatures might be sufficient to destroy the swarm strider.

Clinging Remnants — A swarm strider's melee Strikes and ranged Strikes made against targets within their weapon's first range increment deposit biting vermin on the target, dealing 4d4 persistent piercing damage.

Draw Bugs (healing) — The swarm strider draws more arthropods from the environment around them to reconstitute some of their damaged body. They regain 20 HP. At the GM's discretion, the swarm strider doesn't recover HP in areas where there aren't enough arthropods to call to themselves.

Liquid Delirium (poison) — Saving Throw DC 37 Fortitude

Maximum Duration 6 rounds

Stage 1 4d6 poison and Stupefied 1 (1 round)

Stage 2 4d6 poison and Stupefied 2 (1 round)

Stage 3 4d6 poison, stupefied 2, and Fascinated by a random object (1 round)

Stage 4 Unconscious with no Perception check to wake up (1 round)

Scuttling Shift — The thousand thieves reverts to a swarm using Swarm Getaway, Sneaks up to their Speed, coalesces into their normal form, and Hides. This movement doesn't trigger reactions.

Sneak Attack — The thousand thieves Strikes deal an additional 3d6 precision damage to Off-Guard creatures.

Squirming Injection — The swarm strider Strides. If they end their movement sharing a space with a creature, they deal 6d6 piercing damage to the creature, with a DC 37 Reflex and exposing the target to liquid delirium. The swarm strider can Burrow, Climb, Fly, or Swim instead of Striding if they have the corresponding movement type.

Swarm Getaway (concentrate) — The thousand thieves collapses into a shapeless swarm of their constituent creatures. They drop all but up to 3 Bulk of held, worn, or carried objects in their possession.

In this form, the thousand thieves can't use attack actions and can't cast spells, but they can move through areas small enough for their constituent creatures to fit without having to Squeeze. They can use the same action to coalesce from their swarm shape back into their normal form.

As the swarm moves, the thousand thieves carries these objects if they can fit through the spaces the swarm moves through. The thousand thieves automatically dons any of the objects they desire when they reform. If the thousand thieves is Hidden, Swarm Getaway doesn't reveal their location.