Clockwork Centipede larval stage

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

Siege Monster. The centipede deals double damage to objects and structures.

Writhing Terror. Any enemy outside the centipede that starts its turn within 20 feet of it must succeed on a DC 18 Wisdom saving throw or be frightened until the start of the enemy’s next turn. If the enemy’s saving throw is successful, it is immune to this centipede's Writhing Terror for the next 24 hours.

Multiattack. The centipede makes three attacks — one with its slam and one with its gear throw.

Slam. Melee Weapon Attack: +6 to hit, reach 20 ft., one target. Hit: 12 (2d12 + 6) bludgeoning damage, and the centipede can push the target up to 20 feet away from it.

Gear throw. Ranged Spell Attack: +6 to hit, range 200 ft., one target. Hit: 18 (4d8) force damage, and if the target is a creature, it is knocked prone.

Igniting Beam (Recharge 5–6). The centipede fires a beam of energy from its amber eyes in a 60-foot line that is 10 feet wide. Each creature in the line must make a DC 15 Dexterity saving throw, taking 15 (3d10) radiant damage on a failed save, or half as much damage on a successful one. A creature reduced to 0 hit points by this beam catches fire.

Bonus action: Curl into a ball, which increases its AC to 19. Needs one action to uncurl.