Bone Break

Dark magic suffuses your hand in an attempt to crush the bones of a creature that you can see within range. The target must make a Constitution saving throw. On a failed saving throw, the target takes 4d6 force damage, and until the end of its next turn, its speed is halved and it has disadvantage on weapon attacks. On a successful save, it takes half as much damage and suffers no other effects. If the target is undead, it has disadvantage on the saving throw.

Using a Higher-Level Spell Slot. The damage increases by 1d6 for each spell slot level above 2.