Amphibious. The xolalcha can breathe air and water.

Multiattack. The xolalcha makes one Bite attack and one Tail attack. It can replace the Bite attack with its Head Slam attack (if applicable).

Bite. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 18 (2d10+7) piercing damage, and the target is grappled (escape DC 16). Until this grapple ends, the target is restrained, and the xolalcha can't bite another target.

Tail. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 24 (3d10+7) bludgeoning damage.

Head Slam. Melee Weapon Attack: +8 to hit, reach 10 ft., one grappled target. Hit: 23 (3d10+6) bludgeoning damage. The target is no longer grappled or restrained by the xolalcha and lands prone 10 ft. away from the xolalcha.

Acid Blast. The xolalcha regurgitates acid in a 30 ft. cone. Each creature in that area must make a DC 14 Dexterity saving throw, taking 32 (4d10+10) acid damage on a failed save or half as much damage on a successful one. After using this attack, roll a d6. On a roll of 1, the xolalcha runs out of acid to regurgitate and loses this trait. If the xolalcha still has this trait when it dies, acid erupts from its corpse dealing 13 (2d12) acid damage to all creatures in a 10-ft radius.