Bond Flesh

You gesture towards the target creature and make their skin bond to any material it's in contact with. On a failed CON. saving throw (DC16), figure out damage depending on what exactly happens, but just the base traumatic experience of having your body grow at an unnatural rate hurts... like a lot. Take at least 1d6 necrotic damage because having your body go through that sort of transformation is very painful, then add whatever damage you think fits if any other damage is needed at all (DM's choice obviously). This spell can be upcasted at 5th level, 7th level and 9th level, for increased effects. At 5th level, the base damage is 2d6 and the save is DC18. 7th level,  base 3d6 and save of DC20. 9th level, base 4d6 necrotic + 3d6 piercing as the creature's bones start to grow and puncture their innards (DC22). In addition to the extra damage and harder save, when upcasted to 9th level, a second effect occurs calling 'Calcify'. On the failed CON. (DC22) saving throw, the targeted creature becomes petrified as their skin calcifies, encasing them in their own bones.