uncommon ce medium aberration swarm 

Perception +25; darkvision, tremorsense (imprecise) 30 feet

Languages Aklo, Common

Skills Acrobatics +24, Deception +28, Intimidation +26, Occultism +27, Society +23, Stealth +28

Str +5 Dex +8 Con +5 Int +5 Wis +4 Cha +8

AC  36; all-around vision; Fort +23, Ref +28, Will +26

HP 200, fast healing 10; Immunities poison, precision, disease, paralyzed, swarm mind, unconscious; Weaknesses area damage 10, splash damage 10; Resistances physical 10

Discorporate When the worm that walks is reduced to 0 HP, it discorporates and the component worms that make up its body disperse in every direction. If even a single worm escapes, the worm that walks will eventually re-form using a process that typically takes 1d10 days. While the exact circumstances and surroundings determine how long the worm that walks's foes have to dispatch the fleeing worms before they escape, usually its foes have only a single round. Typically, this requires the application of an area effect or splash weapon within 1 round to the space where the worm that walks collapsed. After any amount of area or splash damage is dealt to that space, the character dealing the damage must attempt a DC 15 flat check. Each subsequent area or splash damage effect performed on the area reduces the DC of this flat check by 2, to a minimum of DC 5. If any of these flat checks succeed, none of the worms escape, and the worm that walks is destroyed permanently. At the GM's discretion, clever means of trapping or otherwise detaining the vermin may extend the time allowed to finish off the worm that walks.

Speed 30 feet

Melee [>] tendril +29 (reach 10 feet), Damage 4d8+14 persistent piercing damage

Occult Spontaneous Spells DC 34, attack +26; 7th (3 slots) phantasmal killer, visions of danger, warp mind; 6th (4 slots) dispel magic, dominate, paranoia, summon entity; 5th (4 slots) black tentacles, mind probe, phantom pain, subconscious suggestion; 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 (7th) daze, detect magic, light, mage hand, shield

Squirming Embrace [>] 5d8 piercing, DC 32

Swarm Shape [>] (concentrate) The worm that walks collapses into a shapeless swarm of worms. It drops all held, worn, and carried items. While discorporated, the worm that walks can't use attack actions and can't cast spells, but it can move through areas small enough for its individual worms to fit without having to Squeeze. It can use the same action to coalesce back into its normal form.

Bestiary 2, page 297.