Energy Shield

Upon casting this spell you surround yourself in a swirling field of energy of your choosing, fire, cold, acid, lightning, or poison. The energy field provides 1/2 cover while it lasts and if you are struck by a melee attack the field will discharge 1d8 of it's energy to the attacker. The spell can produce 4 such discharges before all the energy is gone, ending the spell. When you cast this spell using a higher spell slot you gain an additional discharge for each spell slot above second.