This is a picture of Omega Mouse, leader of the Heroes of Zoolok, the premiere superhero team of the other-dimensional world of Zoolok, a world populated by anthropomorphic animals at a 1940s level of technology. Omega Mouse was a physicist named Kesu Etojach who was accidentally exposed to a lethal dose of radiation while working in his laboratory. Instead of killing him, the radiation activated a latent mutation in his genes. It fortified his molecular structure, endowing him with tremendous strength and resistance to harm. His body can withstand a direct hit from an artillery shell without injury. He does not require food or oxygen, his metabolism being powered entirely by atomic energy, and can survive unprotected in the vacuum of space. He can also expel alpha particles from his body in any direction he chooses, giving him the ability to fly. With sufficient time, he can attain velocities close to the speed of light. However, he requires daily exposure to hard radiation, or his powers fade and he becomes a normal mouse again. Normally, he either enters a radium-filled vault in Heroes Headquarters to replenish his body's supply of atomic energy, or flies into space to bask in the ambient radiation there, though the latter takes longer due to the radiation in space being more diffuse. In emergencies, he swallows a radium pill he keeps in a lead-lined compartment in his belt buckle.
Omega Mouse is the most powerful hero on Zoolok, and has dedicated his life to truth, justice, freedom, and the protection of all species. He appears in several stories I have posted. Check them out!