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From Pathfinder #173: Doorway to the Red Star, which isn't enabled.

King of Biting Ants

CREATURE 19
UNIQUEMEDIUMABERRATIONEVILLAWFULSWARM

Male worm that walks sorcerer

Perception +32; darkvision, tremorsense (imprecise) 30 feet
Languages Akitonian, Aklo, Chthonian, Common, Diabolic
Skills Acrobatics +36, Arcana +34, Crafting +34, Deception +38, Intimidation +38, Occultism +34, Society +32, Stealth +36
Str +5, Dex +9, Con +6, Int +5, Wis +5, Cha +9
Items Wand of Manifold Missiles (7th-Rank Spell)
Tremorsense (Imprecise) 30 feet

Tremorsense allows a monster to feel the vibrations through a solid surface caused by movement. It is an imprecise sense with a limited range (listed in the ability). Tremorsense functions only if the monster is on the same surface as the subject, and only if the subject is moving along (or burrowing through) the surface.

AC 44 (all-around vision); Fort +31, Ref +36, Will +32
HP 300; Immunities disease, paralyzed, poison, precision, swarm mind, unconscious; Weaknesses area damage 15, splash damage 15; Resistances physical 15
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.

Counterspell
Trigger A creature Casts a Spell the King of Biting Ants knows
Effect The King of Biting Ants expends a spell slot to counter the triggering creature's casting. The King of Biting Ants loses his spell slot as if he had cast the triggering spell. He then attempts to counteract the triggering spell.
Discorporate

When the King of Biting Ants is reduced to 0 HP, he discorporates, and the component ants that make up his body disperse in every direction. If even a single ant escapes, the King of Biting Ants will eventually re-form using a process that typically takes 1d10 days.

Applying area damage immediately after the King of Biting Ants is killed prevents his return.

Speed 30 feet, climb 20 feet
Melee Tendril +34 (reach 10), Damage 4d10+15 piercing plus Swarming Bites
Occult Spontaneous Spells DC 44, attack +34; 10th (2 slots) Time Stop, Visions of Danger (Biting Ants Only); 9th (3 slots) Foresight, Wail of the Banshee, Weird; 8th (4 slots) Disappearance, Maze, Mind Blank, Prismatic Wall, Dispel Magic; 7th (4 slots) Visions of Danger (Biting Ants Only), Warp Mind, Phantasmal Killer, Dispel Magic; 6th (4 slots) Dominate, Teleport, Slow, Paranoia; 5th (4 slots) Black Tentacles, Mind Probe, Subconscious Suggestion, Phantom Pain; 4th (4 slots) Dimension Door, Modify Memory, Suggestion, Veil; 3rd (4 slots) Dream Message, Haste, Hypercognition, Slow; 2nd (4 slots) Comprehend Language, Illusory Creature, Mirror Image, Undetectable Alignment; 1st (4 slots) Charm, Illusory Disguise, Mindlink, Ray of Enfeeblement; Cantrips (10th) Daze, Detect Magic, Light, Mage Hand, Shield
Squirming Embrace

The King of Biting Ants Strides to a creature, ends his movement sharing a space with it, and deals 3d8 piercing damage and 3d8 poison damage to it (DC 39 basic Reflex save).

A creature that fails this save also takes 2d8 persistent piercing damage.

Swarm Shape (concentrate)

The King of Biting Ants collapses into a shapeless swarm of ants. He drops all held, worn, and carried items.

While discorporated, The King of Biting Ants can't use attack actions and can't cast spells, but he can move through areas small enough for his individual ants to fit without having to Squeeze. He can use the same action to coalesce back into his normal form.

Swarming Bites

While a creature is taking persistent piercing damage from the King of Biting Ants's tendril Strike or Squirming Embrace, or while within a Visions of Danger area that it has not disbelieved, it is also Clumsy 1.

If the creature attempts a concentrate or manipulate action while affected, it must succeed at a DC 5 flat check or the action is lost; roll the check after spending the action, but before any effects are applied.

Effect: Swarming Bites

Pathfinder #173: Doorway to the Red StarOGL