Atomic rearranging

You touch a creature causing their body to writhe and squirm and take 3d8 psychic damage on a fail and half as much on a success, the creature then makes a dexterity saving throw or be knocked prone, at the beginning of its turn it may redo the save or take 2d8 psychic damage and stay prone.

 When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 1d8 for each slot level above 2nd