Thorn's Kiss

The metal of a sword, axe, spear, or dagger you are holding is imbued with Holly Thorn's sadistic fervor. Choose acid, cold, fire, lightning, poison, psychic, or thunder. Until the spell ends, add 1d4 of the chosen type to the weapon's damage die. The weapon also becomes magical, if it isn't already. The spell ends if you cast it again or if you let go of the weapon.