Bending Bones. The abyssal boneclaw can move through a space as narrow as 2 feet wide without squeezing.

Immutable Form. The abyssal boneclaw is immune to any spell or effect that would alter its form.

Rejuvination. While its master lives, a destroyed abyssal boneclaw gains a new body in 1d6 hours, with all its hit points. The new body appears within 1 mile of the boneclaw's master.

Shadow Stealth. While in dim light or darkness, the abyssal boneclaw can take the Hide action as a bonus action.

Turn Immunity. The abyssal boneclaw is immune to effects that turn undead.

Undead Fortitude. If damage reduces the abyssal boneclaw to 0 hit points, it must make a Constitution saving throw with a DC of 5 + half the damage taken, unless the damage is radiant. On a success, the boneclaw drops to 5 hit points instead.

Multiattack. The abyssal boneclaw makes two claw attacks.

Corpse Consumption. The abyssal boneclaw gains 15 temporary hit points and grows 6 inches for every dead creature it ingests. It can ingest only one dead creature per round. The dead creature must be Small or Medium in size and have a skeleton made of bones. It can have no more than 6 dead creatures ingested at a time in this way. This effect lasts until the next dawn.

Piercing Claw. Melee Weapon Attack: +11 to hit, reach 15 ft., one target. Hit: 28 (3d12 + 5) piercing damage. If the target is a creature, the abyssal boneclaw can pull the target up to 15 feet toward itself and the target is grappled (escape DC 19). The abyssal boneclaw has two claws. While a claw grapples a target, the claw can attack only that target.

Shadow Jump. If the abyssal boneclaw is in dim light or darkness, each creature of the abyssal boneclaw's choice within 5 feet of it must succeed on a DC 19 Constitution saving throw or take 44 (5d12 + 5) necrotic damage. The abyssal boneclaw then magically teleports up to 60 feet to an unoccupied space it can see. It can bring one creature to an unoccupied space it can see within 5 feet of its destination. The destination spaces of this teleportation must be in dim light or darkness.

Deadly Reach. In response to a visible enemy moving into its reach, the abyssal boneclaw makes one claw attack against that enemy. If the attack hits, the abyssal boneclaw can make a second claw attack against the target.