pf2e.fyi
From Pathfinder Society Scenario #2-05: Balancing the Scales, which isn't enabled.

Ash Skeleton (3-4)

CREATURE 3
UNCOMMONLARGEEVILMINDLESSSKELETONUNDEADUNHOLY
Perception +7; darkvision
Skills Athletics +10, Deception +8, Stealth +8
Str +5, Dex +1, Con +3, Int -5, Wis +0, Cha +1
AC 18; Fort +10, Ref +8, Will +5
HP 30, void healing; Immunities bleed, death effects, disease, paralyzed, poison, unconscious; Resistances cold 5, electricity 5, fire 5, piercing 5, slashing 5
Crumble
Trigger The ash skeleton is critically hit
Effect The ash skeleton crumbles to ash, and the attack deals only normal damage
Void Healing

A creature with void healing draws health from void energy rather than vitality energy. It is damaged by vitality damage and is not healed by vitality healing effects. It does not take void damage, and it is healed by void effects that heal undead.

Speed 25 feet
Melee Jaws +12 (reach 10, unarmed), Damage 2d6+5 piercing
Melee Claw +12 (agile, reach 10, unarmed), Damage 1d8+5 slashing
Ash Form

The ash skeleton crumbles to ash or reforms in a standing position. While ash, the ash skeleton is Immobile, Off-Guard, and has an automatic result of 28 on Deception checks and DCs to pass as an inanimate pile of ash or layer of soot.

The ash skeleton can remain in this ash form indefinitely.

Rend

Claw

A Rend entry lists a Strike the monster has.

Requirements The monster hit the same enemy with two consecutive Strikes of the listed type in the same round.
Effect The monster automatically deals that Strike's damage again to the enemy.

Pathfinder Society Scenario #2-05: Balancing the ScalesOGL