Ancestral Stag Sprite

Charge. If the Ancestral  Stag moves at least 20 feet straight toward a target and then hits it with a Gore attack on the same turn, the target takes an extra 7 (2d6) damage. If the target is a creature, it must succeed on a DC 14 Strength saving throw or be knocked prone.

One with Earth. As a bonus action, the Ancestral Stag Sprite can magically shift from the Material Plane to the Ethereal Plane and then teleport 20ft to an empty location. On the Ancestral Stag's next turn, it must use its bonus action to return to the Material Plane, rising up through the ground. 

Gore. Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: 11 (2d6 + 3) piercing damage.

Hooves. Melee Weapon Attack: +5 to hit, reach 5 ft., one prone creature. Hit: 22 (3d8 + 3) bludgeoning damage.

Sleep Breath. The Ancestral Stag Sprite exhales an odourless, faint blue rolling gas, illuminated by white flame in a 5ft cone up to 15ft. Roll 4d12.
The total is how many hit points of creatures this spell can affect. Starting with the creature in this cone that has the lowest current hit points, each creature affected by this spell falls unconscious until the end of their next turn, the sleeper takes damage, or someone uses an action wake the sleeper. Subtract each creature’s hit points from the total before moving on to the creature with the next lowest hit points. A creature’s h⁠⁠it points must be equal to or less than the remaining total for that creature to be affected.

Undead and creatures immune to being charmed aren’t affected by this attack.