Promethean Skull-Gun. When this creature hits 0 hit points, it activates the Promethean Skull-Gun affixed to its head. All players in a 30 foot cone in front of the creature must make a DC 16 Dexterity saving throw. All players who fail this throw take 8d6 acid damage, while all players who succeed take half of that damage.

Multiattack. This creature can make 2 attacks, either with its Vampiric Blade or Acidic Gunk Flintlock.

Vampiric Blade. Melee Weapon Attack: +6 to hit, 1 target. Hit: 15 (3d8+3) slashing damage. If the attack hits, this creature heals 1/2 of the damage dealt, as well as that value being subtracted from the creature hit's maximum hit points. The maximum hit point value is regained when the creature hit completes a long rest.

Acidic Gunk Flintlock. Ranged Weapon Attack: +8 to hit, range 75/200 ft., 1 target. Hit: 15 (2d10+5) acid damage.

As a bonus action, this creature can travel to any spot within 30 feet of it. During this travel, the creature is entirely invulnerable, and almost invisible. If this creature ends its turn inside a solid object, it take 5(1d10) force damage. This action has a recharge time of 2 turns.

Blast Kick. As a reaction when being hit with a melee attack, this creature can use a kick attack with a +3 to hit. If hit, the player hit takes 1d6+3 bludgeoning damage.