Parasite

Rudolph "Rudy" Jones, alias Parasite, was originally a menial laborer who was transformed while working as a janitor at the Pittsburgh branch of S.T.A.R. Labs.

Origins
While working as a janitor at STAR Labs, Jones opened a waste container believing it contained something of value he could steal, and was exposed to a strange form of radiation which changed him into the bald, purple-skinned Parasite. Jones now had the ability to absorb the life energy of others, leaving behind a smoldering skeleton. This power was necessary for his survival, as his own body is in a constant state of hunger for energy that it can't sustain on its own.

Year Zero
Being driven by a singular drive, hunger, Rudy set out to the world to consume. It is through this that he came to blows with Superman at a Casino, after draining a few people to death. The battle between them would progress, and Superman would come to learn the foe he was facing was indeed a Parasite, as he chipped away at his energy and life force.

The battle eventually progressed in scale, involving Batman of Gotham and Wonder Woman of Themyscira. Eventually, the Parasite was defeated by the trio. Batman, researching the Parasite, came to the conclusion that he didn't have any means of holding him and thusly he handed Parasite over to Wonder Woman, who then imprisoned Parasite on Themyscira until further notice.

Powers

 * Unique Physiology
 * Energy Absorption: Parasite is able to absorb the life energy of other beings leaving withered corpses. He is also able to absorb virtually any other energy form and use it. Not only does he sap the life energy out of his victims, he can actually become his victims right down to their DNA. He can hold on to the energy he absorbs for quite a while, and he can absorb energy for up to a 20-foot radius, with increasing intensity the closer one gets to Parasite. The energy he absorbs can also be used to heal himself, and he can also gain memories through absorption of someone's life force.
 * Power Absorption: Parasite is able to absorb the powers of his victim (also known as "Power-Theft"). He can only sustain a certain amount of powers at a time, otherwise previous powers will be either temporarily disabled or weakened. This ability can also cause him to go through: body changes, power fluctuation, knowledge assumption and more.
 * Enhanced Strength
 * Enhanced Agility
 * Enhanced Stamina