Vile Vortex

You summon a massive, whirling, column of foul atrophying mist and miniature ice shards. A 30 ft. tall, 10 ft. radius vortex of unnaturally frigid whirling haze surrounds you which absorbs light and heat in such a way that the haze effectively shrouds you in magical darkness and gives you resistance to fire damage while within its area of effect. If you can't see through magical darkness, you are blinded for the spell's duration. When a creature other than the caster enters the vortex for the first time or starts it's turn within it, it is blinded unless it can see through magical darkness and must make a CON saving throw or take 6d10 cold damage and have disadvantage on CON saves until the end of it's next turn. If it saves, it takes half damage and doesn't suffer any ill effects. The cold damage this spell does ignores cold damage resistance and treats immunity to cold damage as resistance to cold damage instead. 

At Higher Levels.  At 9th level, if you wish to dismiss the vortex prematurely, you can choose to do so in a forceful manner by taking an action to draw in the Delbanite composing the vortex while compressing it, and then releasing it outwards using a bonus action in a powerful 20 ft. radius explosion (spherical area of effect) dealing 12d10 cold damage and 12d10 slashing damage . Any creature within the explosion radius must make a DEX save, or it takes full damage and it's current hp after taking the damage from the explosion is now it's permanent max hp unless healed by a Greater Restoration or similar greater spell due to it's body being shredded by thousands of fast moving ice shards and bombarded with high concentrations of frigid atrophic mist. Succeeding on the DEX save means a creature avoids the majority of the blast and only takes half of the damage. Also, only half of the damage taken is subtracted from it's max hp.