You allow long-forgotten fighting instincts to boil up to the surface. For the duration of the spell, whenever the target deals damage with an unarmed strike or natural weapon, it deals 1d4 extra damage.
Using a Higher-Level Spell Slot. When you cast this spell with a 3rd-level spell slot, the extra damage increases from 1d4 to 1d6. When you cast this spell with a 5th-level spell slot, the extra damage increases to 1d8.
When you cast this spell with a 7th-level spell slot, the extra damage increases to 1d10.