Angon alien parasite

"And I figured out which alien! Parasitus alienus, if we're going by the Wile E. Coyote classification system. It's an alien parasite, guys. Come on. It's probably from the Angon system. Most likely got stuck here during the ice age. So, it finds a host, feeds whatever energy the host comes into contact with, turning them into those husks we found."

- Winn Schott

Unnamed alien parasite nicknamed Parasitus alienus and presumed to be from Angon system was an alien part of a supervillain Parasite formed by him with a Human scientist Rudy Jones.

Biography
At some point in time (theorized by Winn Schott to be ice age) alien parasite from Angon system ended up on Earth, in Norway. Posessing a wolf it used its body to survive, until it was uncovered by Thorul Arctic Research Station.

Freed during the autopsy of the wolf, parasite posessed Rudy Jones by crawling into his head and later proceeded to kill everyone else on the station. Rescued by the D.E.O., Jones was taken back to National City, where the parasite start to take over Jones and began targeting anti-global warming politicians. Despite Supergirl and Martian Manhunter tried to stop him, eventually he drained the powers of two people, leaving J'onn in critical condition and transformed into a larger and monstrous purple alien-human hybrid.

Mon-El and Guardian teamed-up to fight against Parasite who was eventually beaten by Supergirl by using plutonium from a nuclear power plant, completely obliterating him.

Parasite creature was later temporarily brought back to life via Mxyzptlk's reality warping.

Powers

 * Posession: Crawling physically into the living being, parasite was able to fully take control of his host's body, even physically re-shaping it for its survival.
 * Energy/Power absorption: Alien parasite was able to absorb the life energy of other beings, leaving withered corpses. After contact with Supergirl, parasite gained her Kryptonian physical abilities and later, the physical abilities of the Martian Manhunter, which mutated him into a monster. Unlike humans, both Supergirl and Martian Manhunter were able to survive his absorption of their power, though each of them were left unconscious in a withered state and the latter was unable to recover on his own without a blood transfusion from M'gann M'orzz.

Weaknesses

 * Plutonium-239: Alien parasite's powers were overwhelmed by it, causing him to be painfully disintegrated.

Behind the scenes

 * In the DC comics Angon is an alien parasite villain and one of the Bloodlines Parasites, a race of highly advanced and ferocious dragon-like beasts that came to Earth during the events of "Bloodlines". Although Angon had no relation to Rudy Jones in the comics, here it was the catalyst of his mutation, which is also a part of the character as Bloodlines parasites were responsible for mutating several humans into super-powered beings known as New Bloods.
 * In addition while in original comics Angon is character's name here it is a name of his homeworld planet system.
 * On an unrelated note alien parasite's physical appearance and method of entry is based on Mister Mind, an evil telepathic space-worm from the planet Venus who is an enemy of Captain Marvel.