Bio: Half-Life was a vampire-like creature who drained life energy from living beings in order to sustain himself. In his natural state, he looked like a zombie, but when he absorbed a life he would temporarily appear young and handsome. He was even able to absorb the Hulk's superhuman strength. The Hulk still managed to defeat the creature by outsmarting it.
Through keen powers of observation, the Grey Hulk noticed that Half-Life was mentally ill and had ambivalent feelings about needing to kill innocent people to sustain his existence. The Hulk then used psychology to convince Tony Masterson to kill himself.