Black Scorpion

Amorphous. The black scorpion can move through a space as narrow as 1 inch wide without squeezing.

Corrosive Form. A creature that touches the black scorpion or hits it with a melee attack while within 5 feet of it takes 4 (1d8) acid damage. Any nonmagical weapon made of metal or wood that hits the black scorpion corrodes. After dealing damage, the weapon takes a permanent and cumulative −1 penalty to damage rolls. If its penalty drops to −5, the weapon is destroyed.

Nonmagical ammunition made of metal or wood that hits the black scorpion is destroyed after dealing damage.

The black scorpion can eat through 2-inch-thick, nonmagical wood or metal in 1 round.

Spider Climb. The black scorpion can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Multiattack. The scorpion makes three attacks: two with its claws and one with its sting.

Claw. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 6 (1d8 + 2) bludgeoning damage plus 18 (4d8) acid damage, and the target is grappled (escape DC 12). In addition, nonmagical armor worn by the target is partly dissolved and takes a permanent and cumulative −1 penalty to the AC it offers. The armor is destroyed if the penalty reduces its AC to 10. The scorpion has two claws, each of which can grapple only one target.

Sting. Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 7 (1d10 + 2) piercing damage, and the target must make a DC 12 Constitution saving throw, taking 22 (4d10) acid damage on a failed save, or half as much damage on a successful one.   In addition, nonmagical armor worn by the target is partly dissolved and takes a permanent and cumulative −1 penalty to the AC it offers. The armor is destroyed if the penalty reduces its AC to 10.

Split. When a black scorpion that is Medium or larger is subjected to lightning or slashing damage, it splits into two new black scorpions if it has at least 10 hit points. Each new black scorpion has hit points equal to half the original black scorpion's, rounded down. New black scorpions are one size smaller than the original black scorpion.