Amphibious. The axolotl can breathe air and water.

Regeneration. The axolotl regains 10 hit points at the beginning of each of its turns.

Keen Smell. The axolotl has advantage on Wisdom (Perception) relying on smell.

Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 13 (3d6 + 3) piercing damage, and the target is grappled (escape DC 14). Until this grapple ends, the target is restrained, and the axolotl can't bite another target.

Swallow. The axolotl makes one bite attack against a Large or smaller target it is grappling. If the attack hits, the target is swallowed, and the grapple ends. The swallowed target is blinded and restrained, it has total cover against attacks and other effects outside the axolotl, and it takes 15 (6d4) acid damage at the start of each of the axolotl’s turns. The axolotl can have only four Tiny targets, two Medium or Small targets, or one Large target swallowed at a time. If the axolotl dies, a swallowed creature is no longer restrained by it and can escape from the corpse using 15 feet of movement, exiting prone.

Limb. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 10 (3d4 + 3) bludgeoning damage