Blanket of Miasma (Legacy)

A foul congregation of dense mist emits from a point within range that you can see within 60 ft. The mist spreads to an area of 30ft radius, rises to 15 ft high and spreads around corners and through any opening wider than 1 inch wide. The mist heavily obscures the area. 

Creatures that are within the radius when the spell is cast or who start their turn in it must make a constitution saving throw or take 5d6 poison damage and become poisoned for one round as disease permeates their body. Creatures that succeed on their saving throw take half damage and are not poisoned. 

Any creature exposed to the mist must continue making saving throws against it until they succeed 3 times, becoming immune to the mist for 24 hours. If a creature fails 3 saves they take 10d6 poison damage, are poisoned for 24 hours and can no longer regain hit points. They also take another 10d6 poison damage every 24 hours. 

The caster is immune to the mist completely but is still under the effects of its obstruction. Additionally, as a bonus action the caster may choose any unoccupied space within the radius of the mist and teleport to it so long as they are within 60 ft of it.

Enemies within the mist have disadvantage on their saving throw. This effect ignores poison resistance however creatures with resistance to poison damage have advantage on the saving throw.