Avatar of the Air Mask

Air Form. The avatar can enter a hostile creature's space and stop there. It can move through a space as narrow as 1 inch wide without squeezing.

Death Throes. When the avatar dies, it explodes and each creature and object within 15 feet of it must make a DC 14 Strength saving throw. A target is pushed back 60 feet on a failed, or half as far on a successful one. If the target then comes into contact with a hard surface or heavy object, the target takes 3 (1d6) damage per 10 feet moved. The explosion destroys the avatar, leaving only the mask.

Flyby. The avatar doesn't provoke opportunity attacks when it flies out of an enemy's reach.

Multiattack. The avatar makes three slam attacks. 

Slam. Melee Weapon Attack:  +7 to hit, reach 5 ft., one target. Hit: 15 (2d10 + 4) bludgeoning damage, and the target must succeed on a DC 14 Strength saving throw or be pushed back 10 feet. 

Updraft (Recharge 5-6). All creatures and objects in the elemental's space are flung 30 feet directly upwards. A creature can make a DC 14 Dexterity saving throw to grab onto a fixed object it can reach, thus avoiding the fall.
If the target then comes into contact with a hard surface or heavy object, it strikes it just as it would during a normal downward fall. If an object or creature reaches the top of the area without striking anything, it remains there floating, for the duration.
At the beginning of the avatar's next turn, affected objects and creatures fall back down.

Disperse. The avatar momentarily dissipates, negating all effects of one weapon attack that would hit it. To do so, the avatar must see the attacker.