Trample on an instant or sorcery is similar to how it works on an attacking creature. If Super-Duper Death Ray would deal more damage that what it would take to destroy the creature (called “excess damage”), it deals the excess to the creature’s controller. For example, if you aim Super-Duper Death Ray at a 1/1 creature, it will deal 1 damage to the creature and 3 damage to its controller.