Astral Sprite

Keen Sight. The sprite has advantage on Wisdom (Perception) checks that rely on sight.

Shapechanger. The sprite can use its action to polymorph into a Small or Medium humanoid it has seen, or back into its true form. Its statistics, other than its size, are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.

Mimicry. Astral Sprite can mimic sounds they have heard, including voices. A creature that hears the sounds they make can tell they are imitations with a successful Wisdom (Insight) check opposed by your Charisma (Deception) check.

Astral Traveler. The sprite latches onto those traveling between the material plane and the beyond, using their vessels to sneak into the material plane should an unknowing traveler awake.

Rotting Gaze. The sprite targets one creature it can lock gaze with within 30 feet of it. The target must succeed on a DC 15 Wisdom saving throw against this magic or take 10 (3d6) necrotic damage.

Draining Gaze. Ranged Spell Attack:  +4 to hit, range 60 ft., one target. Hit: 9 (2d6 + 3) necrotic damage, and the target's Strength score is reduced by 1d4. The target must be able to see the Sprite for the attack to be effective. The target dies if this reduces its Strength to 0. Otherwise, the reduction lasts until the target finishes a short or long rest.

If a non-evil humanoid dies from this attack, a sprite rises from the corpse 1d4 hours later.

Weird Insight. The sprite targets one creature it can see within 30 feet of it. The target must contest its Charisma (Deception) check against the sprite’s Wisdom (Insight) check. If the sprite wins, it magically learns one fact or secret about the target. The target automatically wins if it is immune to being charmed.