While Maggott was never the most popular X-Man, he still played a key role during the team's most popular era.
The character was created by Scott Lobdell and Joe Madureira for 1997's Uncanny X-Men #345. When he debuted, Maggott appeared to be a large, super-strong mutant with blue skin, who happened to have a pair of matter-eating pet slugs as his pets. Well, these slugs were actually Maggott's digestive system, and they transformed him into his blue-skinned form after feasting. He also has psychometric abilities that let him mentally visualize the history of his immediate surroundings.
Eventually, Maggott was revealed to be a South African teen named Japheth. Shortly after his odd mutant powers emerged, his father was killed by Afrikaner forces, and Magneto subsequently killed them in an unsuccessful attempt to recruit the young mutant.
After Maggott wandered around the globe for years, one of his slugs helped save Cyclops' life. The young mutant subsequently joined the X-Men, though he was only on the team for less than a year before taking off for parts unknown.
After a few years in comic book limbo, Maggott returned, only to be killed in Frank Tieri and Georges Jeanty's Weapon X #5. In that heartbreaking 2004 story, Maggott was captured and executed at Neverland, a mutant internment camp operated by the Weapon X Program. Although Maggott gave one of his slugs to a child so one part of him could live on, the mad scientist Mr. Sinister captured the slug and added it to his collection of mutant genetic material in a cruel twist.
Like dozens of other dead X-characters, Maggott, and one of his slugs, were revived by the psychic vampire Selene in 2009's "Necrosha" storyline. After being freed from Selene's control, Maggott made a few minor cameos and receded into the background of the Marvel Universe once again, until his recent reappearance.
When he first appeared, Maggott was positioned as the next major X-Man. Even though he never evolved into that, Maggott still serves as an important transitional figure in X-Men history.
Before Maggott, the X-Men's newest recruits were aggressively "cool," marketable characters like Cable, Gambit, Bishop and Jubilee. With stylish costumes and impressive superpowers, these were the kinds of characters who could sell action figures and star in Saturday morning cartoons.
While the blue-skinned Maggott initially seemed like another one of those characters, he was too strange to achieve similar success. As the relatively gross nature of his slug-based powers became more evident, that inherent weirdness quickly became his defining quality.
Maggott was hardly the first mutant who was defined by his oddities. The sewer-dwelling mutants of the Morlocks had strange appearances and weird powers long before Maggott, but they were largely secondary characters. However, it's worth noting that Marrow, a pink-haired Morlock with bone spikes protruding from her body, joined the X-Men around the same time Maggott did.
While there were still marketable aspects to both Marrow and Maggott, they made the X-Men a much weirder team. And after their relatively short tenures with the team ended, the X-Men stayed weird.
From the early 2000s onward, several new X-Men have embraced the kind of weirdness that defined Maggott. The semi-transparent Glob Herman looks like a walking illustration from a biology textbook, Shark-Girl is more shark than human, and the potato-shaped Doop defies description. The aggressively cool Fantomex has odd powers that involve his nervous system having been transformed into a sentient flying saucer, and even Beast lost his familiar simian form as he evolved into a stranger, more cat-like creature for a few years.
While the short-lived Generation X revival was built entirely around these kinds of odd characters, weird mutants are a regular feature of the X-Men's world now.
After he left the X-Men, Maggott might've been mocked or written off, but he and his slugs were some of the first harbingers of a new breed of X-Man. If he might've been ahead of his time in the 1990s, maybe Maggott can find a more permanent role in the weirder world of the X-Men that he helped create.