Dimensional Shambler

Look Between. As a bonus action, the dimensional shambler can see 60 feet into any of the Lower Planes when it is on the Material Plane, and vice versa. This sight lasts until the beginning of its next turn. During this time, the dimensional shambler is deaf and blind with regard to its own senses in its current plane.

Maddening Form. When a creature that can see the dimensional shambler starts its turn within 30 feet of the dimensional shambler, the dimensional shambler can force it to make a DC 16 Constitution saving throw if the dimensional shambler is not incapacitated. On a failed save, the creature is frightened until the start of its next turn. If the creature is concentrating on a spell, that creature must succeed on a DC 16 Constitution saving throw or lose concentration on the spell. Unless surprised, a creature can avert its eyes to avoid the saving throw at the start of its turn. If the creature does so, it can't see the dimensional shambler until the start of its next turn, when it can avert its eyes again. If the creature looks at the dimensional shambler in the meantime, it must immediately make the saving throw.

Step Between. As a bonus action, the dimensional shambler can magically shift from the Material Plane to any Lower Plane, or vice versa. It can't bring other creatures with it when it shifts in this way.

Multiattack. A dimensional shambler makes two claw attacks. If both attacks hit the same target, the target is grappled (escape DC 16).

Claw. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 17 (2d10 + 6) slashing damage.

Drag Through. The dimensional shambler shifts through multiple dimensions with a target it is grappling, ending in the same dimension it began. The creature must make a DC 16 Wisdom saving throw, taking 21 (6d6) psychic damage on a failed save, or half as much damage on a successful one.