Additional Legs. Six legs allow the cogwork librarian to climb at a speed equal to its base speed and to ignore difficult terrain.

Piston Reach. The cogwork librarian’s melee attacks have a deceptively long reach thanks to the pistons powering them.

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

Eldritch Power Source. When a cogwork librarian falls to 0 hp, its eldritch battery explodes. Creatures within 10 feet of the cogwork librarian take 14 (4d6) lightning damage, or half damage with a successful DC 14 Dexterity saving throw.

Bound. The cogwork librarian is magically bound to an amulet. As long as the cogwork librarian and its amulet are on the same plane of existence, the amulet's wearer can telepathically call the cogwork librarian to travel to it, and the cogwork librarianknows the distance and direction to the amulet.

Multiattack. The clockwork abomination makes one stab attack and one slam attack.

Stab. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 15 (2d8 + 6) piercing damage.

Slam. Melee Weapon Attack: +9 to hit, reach 15 ft., one target. Hit: 13 (2d6 + 6) bludgeoning damage.

Arc Weapon (Recharge 5-6). The cogwork librarian’s Eldritch Power Source allows it to arc lightning in a 20-foot cone. Targets in this cone take 22 (4d10) lightning damage, or half damage with a successful DC 14 Dexterity saving throw.