The U-Foes are a team of HYDRA backed Scientists who stole a spaceship to duplicate the accident that gave the Fantastic Four their powers.
Vector/ Simon Ultrecht:
The team leader who was given telekinesis
Vapor/ Ann Darrell:
Given the ability to turn into any form of gas.
X-ray/ James "Jimmy" Darrell:
Vapor's brother who can create radiation blasts.
Ironclad/ Micheal Steel:
Body is made out of a living metal, and can control his weight and density.
Behind the Scenes
In the comics, Simon Ultrecht was a rich man who desired power. Upon learning how the Fantastic Four got their abilities, he hired a team to do the same. As the ship entered the Cosmic Storm, Bruce Banner, having just finished a Hulk episode, wandered into their control station. Misunderstanding what was going on, Bruce remotely guided the ship back to Earth. However the newly mutated U-Foes attacked Bruce, believing they could have gotten more power. The team was defeated by the Hulk several times over, however Ironclade specifically broke off from the team to fight the Hulk more than once.