Gibbering

The creature babbles incoherently while it can see any target and isn't incapacitated. Each creature that starts its turn within 20 feet of the creature and can hear the gibbering must succeed on a Wisdom saving throw (DC = 8 + proficiency bonus + Wisdom modifier). On a failure, the target can't take reactions until the start of its next turn and rolls a d8 to determine what it does during its turn. On a 1 to 4, the target does nothing. On a 5 or 6, the target takes no action or bonus action and uses all its movement to move in a randomly determined direction. On a 7 or 8, the target makes a melee attack against a randomly determined target within its reach or does nothing if it can’t make such an attack. (Gibbering Mouther pp. 157, MM)