Clockwork Reliquary

Adamantine Weapons: The Reliquary has adamantine claws and darts that can each score a critical hit on a roll of 19 or 20.

Magic Resistance: The Reliquary has advantage on saving throws against spells and other magical effects.

Magic Weapons: The Reliquary's weapon attacks are magical.

Unstable Mind: The Reliquary's animating spirit carries with it all of the spirit's madness. At the start of its turn there is a 25% chance that it malfunctions. If it malfunctions, it acts as though affected by the confusion spell until the start of its next turn. Once it has malfunctioned, it can't malfunction again until the end of it's next turn.

Multiattack: The Reliquary makes four attacks with its claw or six attacks with its darts. Alternatively, it makes two attacks with its claws and three attacks with its darts.

Claw: Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: 43 (6d10 + 10) slashing damage.

Dart: Ranged Weapon Attack: +9 to hit, range 20/60 ft., one target. Hit: 23 (6d6 +2) piecing damage.

Sphere Discharge (Recharge 5-6): Each creature within a 30 ft. radius must make a DC 18 Constitution saving throw. On a failed save, a creature takes 21 (6d6) lightning damage and is stunned until the end of its next turn. On a successful save, the creature takes half as much damage and isn't stunned.