Homebrew

Traits

Magic Resistance. The waking nightmare has Advantage on saving throws against spells and other magical effects.

Somnophage. At the start of its turn, the waking nightmare gains a number of Temporary Hit Points equal to 5 times the number of creatures with the Unconscious condition within 30 feet of it.

Actions

Multiattack. The waking nightmare makes two Nightmare Touch attacks.

Nightmare Touch. Melee Attack Roll: 1d20+6 to hit, reach 5 ft. Hit: 14 2d10+3 Psychic damage, and the target has the Frightened condition until the start of the waking nightmare's next turn.

Tendrils of Slumber (Recharge 5–6). The waking nightmare conjures spectral tentacles in a 20-foot Cube originating from a point on the ground the waking nightmare can see within 30 feet. The tendrils last for 1 minute or until the waking nightmare uses Tendrils of Slumber again. This area is Difficult Terrain. Wisdom Saving Throw: DC 14, each creature that enters the tendrils for the first time on a turn or starts its turn there (creatures immune to the Frightened condition succeed automatically). First Failure: 11 2d10 Psychic damage and the target has the Restrained condition. The target repeats the save at the start of its next turn if it is still Restrained, ending the effect on itself on a success. Second Failure: The target has the Unconscious condition instead of the Restrained condition. An Unconscious creature wakes up if it takes any damage, leaves the area of the tentacles, or if another creature takes an action to shake it awake.

Terrible Dream (1/Day). Wisdom Saving Throw: DC 14, one Unconscious creature the waking nightmare can see within 5 feet. Failure: 27 5d10 Psychic damage. The target's Hit Point maximum decreases by an amount equal to the Psychic damage taken, and the waking nightmare regains Hit Points equal to that amount.

Bonus Actions

Shadow Stealth. While in Dim Light or Darkness, the waking nightmare takes the Hide action.