Jimmy Darnell was part of a team organized by Simon Utrecht a millionaire, public official, and industrialist who wanted to simulate the crash that led to the powers of the Fantastic Four. He promised each member of the team superpowers due to exposure (although intentional, not accidental) to cosmic radiation. During this launch, Dr. Bruce Banner (known as the Hulk) was on hand at the base, and believing the ship to be having problems, guided it back to Earth. The now-changed humans called themselves the U-Foes (possible in connection with Utrecht's last name) and blamed Banner for cutting short their radiation exposure.
They again battled the Hulk and this time defeated him. In triumph, they exhibited the captive Bruce Banner on national television. However, Banner was freed by Rick Jones, Betty Ross, and the alien Bereet, and Banner transformed into the Hulk and defeated the U-Foes.
X-Ray's body has been bombarded with cosmic rays far greater then that of Human Torch, since then he has received another dose at edge of earth's atmosphere, X-Ray achieved better control over his powers.
Radiated Form: X-Ray has been permanently transformed into a living energy field of quasi-solid radiation. He can't return to human form. Like his sister, he is intangible and mostly invulnerable to physical harm, although he can still be harmed by attacks that damage or disrupt his energy fields, such as a lead pipe used by the Hulk, or the vibranium in Captain America's shield. He can also be defeated if he is drained of his supply of radiation, as Thor once did with Mjolnir.
- Radiated Form Manipulation: X-Ray can transform and emit any and all forms of radiation in the electromagnetic spectrum.
- Radiation Projection: He can project hard radiation as devastating blasts from his hands and emit various wavelengths of heavy radiation from is body. He can focus it in the form of very potent concussive force blasts, shown capable of hurting even the Hulk, or 'negative gamma rays' that can transform the Hulk back into Bruce Banner (which has since become infective to the Hulk).
- Flight: He is capable of flight at unknown speeds.
- Invisibility X-Ray can become Invisible.
Jimmy Darnell has a Master's degree in engineering. Fuel Propulsion Engineer.
X-Ray possesses the normal human strength of a man of his age, height, and build who engages in moderate regular exercise.