Aberrant Ground. The ground in a 10-foot Emanation originating from the mouther is Difficult Terrain.

Gibbering. The mouther babbles incoherently while it doesn't have the Incapacitated condition. Wisdom Saving Throw: DC 10, any creature that starts its turn within 20 feet of the mouther while it is babbling. Failure: The target rolls 1d8 to determine what it does during the current turn: 1-4. The target does nothing. 5-6. The target takes no action or Bonus Action and uses all its movement to move in a random direction. 7-8. The target makes a melee attack against a randomly determined creature within its reach or does nothing if it can't make such an attack.

Bite. Melee Attack Roll: +2, reach 5 ft. Hit: 7 (2d6) Piercing damage. If the target is a Medium or smaller creature, it has the Prone condition. The target dies if it is reduced to 0 Hit Points by this attack. Its body is then absorbed into the mouther, leaving only equipment behind.

Blinding Spittle (Recharge 5-6). Dexterity Saving Throw: DC 10, each creature in a 10-foot-radius Sphere centered on a point within 30 feet. Failure: 7 (2d6) Radiant damage, and the target has the Blinded condition until the end of the mouther's next turn.