Uzollru

Amphibious. The uzollru can breathe air and water.

Magic Resistance. The uzollru has advantage on saving throws against spells and other magical effects.

Stunning Gaze. The uzollru’s eye sheds dim red light in a 60-foot cone as long as it isn't blinded or incapacitated. At the start of each of its turns, the uzollru decides which way the cone faces.

Any creature that isn’t a demon that starts its turn within the cone's area and can see the uzollru must succeed on a DC 16 Intelligence saving throw or be stunned until the start of its next turn. A creature that succeeds on the saving throw is immune to this uzollru’s Stunning Gaze for the next 24 hours.

A creature that isn't surprised can avert its eyes to avoid the saving throw at the start of its turn. If it does so, it can't see the uzollru until the start of its next turn, when it can avert its eyes again. In the meantime, if the creature looks at the uzollru while still within the cone's area, it must immediately make the save.

Multiattack. The uzollru makes two Claw attacks. If the uzollru has at least one creature grappled, it can also make one Tentacles attack against one of the creatures it has grappled.

Claw. Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 18 (3d6 + 8) bludgeoning damage, and if the target is a Huge or smaller creature, it is also grappled (escape DC 22), and it is restrained until the grapple ends. The uzollru has two claws, each one can grapple only one target.

Tentacles. Melee Weapon Attack: +14 to hit, reach 10 ft., one creature. Hit: 15 (2d6 + 8) piercing damage plus 9 (2d8) acid damage. The target’s Hit Point maximum is reduced by an amount equal to the acid damage taken. The reduction lasts until the target finishes a long rest. The target dies if its Hit Point maximum is reduced to 0.

Stare of Madness. The uzollru targets one creature it can see within the area of its Stunning Gaze that can see the uzollru. The target must succeed on a DC 16 Intelligence saving throw or take 27 (6d8) psychic damage and have its Intelligence and Wisdom scores reduced by 1d8, to a minimum of 3. If the creature failed the saving throw by 5 or more, the reduction lasts until the creature is targeted by a greater restoration, heal, or wish spell. Otherwise, the reduction lasts until the target finishes a long rest.