Trainor's career as a superhero begins when he is accidentally exposed to a radioactive field in the atmosphere while piloting a test plane. This experience leaves him radioactive, but also gives him a strange superpower: the ability to release a negatively charged energy being from his body; the being, also referred to as Negative Man, or, later, as the Negative Spirit, can fly at high speed, cause solid objects to explode, and pass through solid materials. It resembles a shadowy silhouette of a human being, surrounded by a bright glow. The being is under Trainor's control and appears at first to have no mind of its own. But Trainor is weak and defenseless while the being is separated from his body; he can only risk sending it forth for 60 seconds at a time without risking death. After his accident, Trainor resembles the Invisible Man; he is forced to wear specially treated bandages over his entire body to protect bystanders from his radioactivity.