Dante's Mortalizer

You create a mote of gravity inside a creature that you can see within range. On a failed constitution saving throw, the outer shell of the creature is pulled inside, revealing it's voulnrable parts. while not enough for bladed weapons or projectiles to slip through, the exposed areas can be targeted by elemental damage (Acid, Cold, Fire, Lightning, Poison). The Target loses one Immunity of the caster's choice and takes 2d10 force damage in the process. On a successful save, the target takes no damage and the immunity is turned into a resistance instead.
A creature that had it's immunity removed this way may repeat the save at the end of it's next turn, on a success the creature gains resistance in that damage type.

If cast at 7th level or higher, the spell does not require concentration to uphold.