One of my favorite comic book characters is Deadpool. Since the very beginning he's actually been a favorite character for a lot of readers and at the same time he's a bit more than that, and also something that Marvel didn't expect in terms of popular interest. Deadpool's popularity has grown enough that he's gotten multiple comic books and even a possible movie deal.
The character is fascinating in his own right, breaking the fourth wall frequently and at the same time playing with a lot of comic book tropes in terms of hero and anti-hero concepts. There's enough character development to keep him interesting, but a lot of the focus is on his humor, self-destructiveness, and the healing factor that keeps him alive despite it all.
Why do I think of Deadpool as a memetic virus? In part, I think of him as this because of how much his character has come to pop up in video games, comics, etc., and in art because he breaks the fourth wall frequently. I see him as an agent of chaos (which can be good). More than that I see him as a sticky character, which is to say he stands out in the minds of the readers in ways other characters don't.
Having been familiar with the various iterations of the character, since he was first invented, its interesting to see how he's evolved from a comic book villain to something more than a comic. I find tracing the history of such entities can be useful for learning if you'll work with them, as well as understanding just how they've changed due to popularity and interest.