Astral Chimera

Ethereal Jaunt: As a bonus action, the chimera can magically shift from the Material Plane to the Ethereal Plane, or vice versa.

Two Heads: The Chimera has advantage on Wisdom (Perception) checks and on saving throws against being blinded, charmed, deafened, stunned, and knocked unconscious.

Wakeful: When one of the chimera's heads in asleep, its other head is awake.

Spellcasting: The astral chimera's spellcasting ability is Charisma (spell save DC 15). The astral chimera can innately cast the following spells, requiring no material components:

At will: detect magic, fog cloud, silent image
1/day each: dispel magic, major image
3/day each: blur, detect thoughts

Multiattack: The chimera makes two bite attacks, and can cast an at-will spell from its innate spell list.

Bite: Melee Weapon Attack: +7 to hit, reach 5 ft., One target. Hit: 14 (3d6 + 4) piercing damage. The target must succeed on a DC 15 Wisdom saving throw or take 18 (4d8) psychic damage, half damage on a success.