Lich Hound

Blood Sense. The lich hound can pinpoint the location of creatures that aren't Constructs or Undead within 60 feet of it and can sense the general direction of such creatures within 1 mile of it.

Keen Hearing and Smell. The lich hound has advantage on Wisdom (Perception) checks that rely on hearing or smell.

Undead Nature. The lich hound doesn't require air, food, drink, or sleep.

Multiattack. The lich hound can use its Eerie Howl. It then makes two Bite attacks. If both attacks hit one creature, the target must succeed on a DC 14 Constitution saving throw or take 7 (2d6) slashing damage and be incapacitated until the end of its next turn.

Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) piercing damage. If the target is a creature, it must succeed on a DC 14 Strength saving throw or be knocked prone.

Eerie Howl. The lich hound releases an eerie howl that fades in and out and echoes strangely. Each creature within 30 feet of the lich hound must succeed on a DC 14 Wisdom saving throw or be frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the lich hound's Eerie Howl for the next 24 hours.

Ethereal Jaunt. The lich hound magically shifts from the Material Plane to the Ethereal Plane, or vice versa.