10 Comic Book Characters Who Are Just TOO POWERFUL!
9. Doomsday
When Doomsday burst onto the scene back in 1992, he instantly became iconic as the first villain to kill Superman. On his way to doing so, he wiped out all the Justice Leaguers who got in his way and destroyed a good chunk of the eastern US to boot. Superman stopped him at the cost of his own life.
At the time, Doomsday had no origin aside from 'space', which made him compelling - who the hell was this grey monstrosity who just wiped the floor with DC's greatest hero? Since then his character has been explained and retconned a few times, taking away the mystery.
His backstory now is that he was a was a genetic experiment to create the ultimate living weapon, cloned and killed over and over again, evolving every time to counteract whatever it was that killed him.
A great example of this is the DCAU version of Doomsday. In one episode, the Justice Lord Superman lobotomizes Doomsday with his heat vision. When they meet again in a later season, Doomsday's skull has grown a thick ridge of bone impervious to heat.
Now, during every fight with Superman or the League, Doomsday evolves, becoming ever stronger and more unstoppable.