Bigby’s Barbarous Bone Removal

You place the bone dust and metal shavings in your hand and then place the other half on your other hand while intoning the incantation. With a horrible, wet squelching sound the bones of the target are ripped from their body leaving behind a mass of blood and flesh. 
This spell deals 12d8+30 bludgeoning damage, constitution saving throw for half damage. If target succeeds on the saving throw they are hurled to the ground and knocked prone. 
Targets killed by this spell can only be brought back with a Wish spell or True Resurrection.