Choking Smog

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

Choking Winds. The foul winds of the elemental pull other creatures in. Any creature that begins its turn within 5 feet of the elemental, and any creature that comes within 5 feet of the elemental for the first time this turn, must make a DC 12 Strength saving throw. On a failure, the creature takes 1d6+2 Bludgeoning damage and 1d6+2 Necrotic damage and is stunned until the end of their next turn.

Deep Haze. The elemental can enter a hostile creature’s space and stop there. A creature who enters or starts its turn in the same space as the elemental must make a DC 12 Constitution saving throw. It takes 2d6 necrotic damage on a failed saving throw.

Arcane Eruption. Whenever the elemental rolls a natural 1 or a natural 20 on any roll, it triggers an Arcane Anomaly. Roll on the Arcane Anomalies table (see Delerium-Tipped Projectile for the table.)

Multiattack. The elemental makes up to five attacks.

Slam. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 2d10 bludgeoning damage + 2d10 necrotic damage.

Hurricane (Recharge 4–6). Each creature in the elemental's space must make a DC 13 Strength saving throw. On a failure, a creature takes 16 (4d8) bludgeoning damage + 16 (4d8) necrotic damage and is thrown 40 feet away from the elemental in a random direction and knocked prone. If a thrown creature strikes an object, such as a wall or floor, the creature takes 4 (2d4) bludgeoning damage for every 5 feet it was thrown. If the creature is thrown at another creature, that creature must succeed on a DC 13 Dexterity saving throw or take the same damage and be knocked prone.

If the saving throw is successful, the creature takes half the bludgeoning damage and isn't thrown away or knocked prone.