34 years ago - Rudy Jones is born.
14 years ago - 20-year-old Rudy gets a job as a janitor in Lexcorp Labs.
11 years ago - 23-year-old Rudy is exposed to waste from Lex Luthor's experiments with alien bio-chemistry, becoming the Parasite... consuming the lifeforce of Superman, temporarily gaining his powers and memories before he is defeated and put in prison.
6 years ago - 28-year-old Rudy discovers ways to alter his body. He escapes and poses as Jimmy Olsen to sneak into the Daily Planet, looking for Superman.
5 years ago - 29-year-old Rudy consumes a small amount of Doomsday, gaining a far more alien, leech-like body. He is knocked to the Moon by the Eradicator who battles him and leaves his husk on the lunar surface.
1 year ago - 33-year-old Rudy is recovered and used by Gorilla Grodd, altering his biochemistry to shield the Legion of Doom headquarters.
Parasite is one of Superman's weirdest baddies, but he's an excellent fit for the Man of Steel, because he presents a particular challenge unique among his army of men in suits and monsterous punching bags. His particular challenge turns Superman's power against him. He BECOMES a massive powerhouse punch-absorbing monster, but Superman's normal "punch the problem until it goes away" strategy just doesn't work, because the more he exposes himself to Parasite, the more he opens himself up to allowing him to absorb more of his life force and grow even stronger. In fact, he can even drain enough of him to actually gain his memories. Superman's secret identity isn't a traditional weakness, but the fact that Parasite regularly abosorbs and forgets that knowledge makes him an particuraly scarry foe, and a great fit for his modern rogue's gallery.
Parasite's Comic History
There really isn't a whole lot about Parasite that has to be explained. He was a pretty standard villain with a pretty standard origin; toxic chemical waste mutated him into a monster that torments the protagonist (I'm fairly sure the same origins apply to at least half of Spider-Man's enemies. and the Ninja Turtles.) He's turned up and been used in a lot of different, intersting ways by various writers, but he's always a cool challenge.
Our Parasite Story
Our big focus in choosing Parasite stories to include comes mostly from wanting to include a few of the versions of the character, because he's had some very neat stylistic interpretations, and we wanted them all to get a spotlight. So while we're starting out with the dumpy, almost human version of Parasite, we also want to see the more sinister, alien versions, as well as the leech-like, menacing monster from All-Star Superman. by giving him several different appearances where he rediscivers new elements of his mutation, or where he's manipulated by consuming Doomsday's life-essense of by the manipulation of Gorilla Grodd, we get to see him shift and change over time.
Older versions of the character (he's actually been around a while) suggested that Parasite's purple appearance was actually some kind of costume, but that obviously got replaced pretty quickly making it his actual skin. This is probably where the idea of him having uniform stripes around his body came from, and they've continued to appear on a lot of depictions of the character, including the Superman Animated Series, which used him to great effect. There's nothing wrong with that, obviously, but when Gary Frank reinterpretted the character for Geoff Johns's Superman: Secret origin and drew him with a dumpy body with a clear streak of lighter pink on his purple belly, it's hard not to think this is a much better starting point for the character. Perhaps when he learns that he can actually mimic people's appearance, that's when we see a more slender, alien-like verison of his regular body.
He's also been drawn as a massive leech-like behemoth by artists like Ed McGuinness (who LOVES drawing huge monsters for his heavily muscled hereos to fight) and that also really clicked as a possible appearance for Parasite. Still, if i had to pick a favorite version of the character, it has to be be the terrifying leech monster from the All-Star Superman animated movie, where he looked right out of a Miyazaki movie. that's the creature he needs to be slowly evolving into.
Most baddies lend themselves to be reinterpreted by the writer and artist currently using them, but this happens to be one of my favorite, because he's so science-fiction body-horror weird that the interpretations of him can vary so widely. His mutated body will definitaly allow him to survive for a long time, and so a generations of heroes grow into prominenc, Parasite is a character that is definitely going to continue to evolve to challenge them in new and unexpected ways. Practically any new creator will almost definitely have their own spin on him, and he has room in is concept to try them all.