Boneweaver

Bone Armor. The Boneweaver is covered in the bones of fallen creatures - while it has these bones, it gains +4 to its AC. When the Boneweaver takes more than 30 damage in a single turn, the bones snap and break, reducing its AC bonus by 1. The Boneweaver can spend 1 minute in a pile of bones, offal, or other sort of corpse to replace any broken bones, restoring its bonus to AC.

Multiattack. The Boneweaver makes three attacks: one Bite, one Claw, and one Sting attack.

Bite. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 15 (3d6+5) piercing damage, and the target must succeed on a DC 17 Constitution saving throw or take 10 (3d6) poison damage. If the poison damage reduces the target to 0 hit points, the target is stable, but Poisoned for 1 hour, even after regaining hit points. While poisoned in this way, it is Paralyzed.

Claw. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 9 (1d8+5) bludgeoning damage, and the target is grappled (Escape DC 19). The Boneweaver has two claws, each of which can grapple one target.

Sting. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 21 (3d10+5) piercing damage, and the target must make a DC 17 Constitution saving throw, taking 22 (4d10) poison damage on a filure, or half as much on a success.