If you were a fan of cartoons around the mid-2000s, you may very well remember Martin Mystery.

For the uninitiated, Martin Mystery was a science fantasy animated series that originally ran from late 2003 to early 2006. The show followed, well, Martin Mystery - an immature and hyperactive, yet fairly capable teenage paranormal investigator who would often battle monsters, ghosts, or other supernatural entities. Joining Martin on his adventures were Diana Lombard, his no-nonsense step-sister, and Java the Caveman, a 200,000-year-old Neanderthal who served as the trio's muscle.

Martin, Diana, and Java went on their various adventures at the behest of The Center, a covert organization tasked with safeguarding the world from paranormal threats. The day-to-day operations of The Center were overseen by an agent going by the codename M.O.M. (who fittingly served as something of a parental figure to Martin and Diana) and her secretary, a tiny green alien named Billy.

RELATED: Line It Is Drawn: Cartoon Kids All Grown Up!

Each episode of Martin Mystery followed more or less the same blueprint. We would be introduced to the supernatural phenomenon of the week before joining the main trio, who were going about their daily lives at Torrington Academy. When The Center would inevitably come calling, the Martin, Diana, and Java would have to drop what they were doing to be briefed by M.O.M. They go on their way, supernatural shenanigans ensue, the mystery is ultimately solved, M.O.M. shows up for a debriefing and everything goes back to normal (until next time, that is.) This formula was simple, yes, but also definitely had legs.

Martin Mystery concluded in March 2006 after a three-season, 66-episode run. It was broadcast on numerous networks, with reruns airing up until about 2008. The show's titular character also returned for a crossover episode with Totally Spies! in 2007 - which isn't exactly surprising, given how similar the two shows were, both in premise and episode structure.

Despite a rather short time on television, as well as the fact that it was relatively esoteric, Martin Mystery has managed to garner a cult following since its cancellation, with many fans demanding a revival. A fourth season was confirmed to be in development back in 2013, but six years later, it has still yet to see the light of day. There have also been murmurs of the first three seasons being remastered and made available on major streaming platforms, but that has also not yet come to fruition.

In the meantime, the dedicated fanbase of Martin Mystery dedicated may remember the series for the approach it took to its subject matter. The show was not afraid to put its characters in genuine peril and fully commit to its horror elements, and some of the creatures the heroes would face were actually pretty creepy as far as TV-Y7 programs go. At the end of the day, however, it was still very much a children's show, being chock-full of bright colors, lighthearted antics, slapstick gags and a general aura of kid-friendly fun. That's why it may surprise some fans to know the original source material is much more adult-oriented.

RELATED: 15 Cartoons From The '00s That Need A Come Back (And 5 That Can Stay In The Aughties)

Created by writer Alfredo Castelli and artist Giancarlo Alessandrini, Martin Mystère was first released by Italian publisher Sergio Bonelli Editore in 1982, pre-dating the TV show by over two decades. After proving to be a huge hit in Italy, the comic was localized for American readers by Dark Horse Comics - who published it stateside as Martin Mystery in 1999. But whereas Dark Horse's version came to an end, the original comic has continued to persevere over the pond, with new issues still regularly being released.

If you were a kid when the Martin Mystery cartoon was first airing, you'll be forgiven for not being aware of the comic's existence, given how far apart the two were first released. Plus, while Castelli was credited as the titular character's creator (as well as a developer on the show), his credit during the title sequence goes by pretty fast. And let's be honest for a second, the vast majority of kids honestly don't read credits to begin with.

However, fans of the animated series may find it an interesting experience to pay a visit to the comics that started it all. Because when you look back on Martin Mystery's history on the page, it becomes immediately clear just how drastic a departure the fan-favorite '00s cartoon truly was.

For starters, Castelli's Martin Mystère features a protagonist almost unrecognizable as the flame shirt-wearing, sci-fi magazine-obsessed high school student seen in the cartoon. Rather, the original Martin from the comics is a grown man with a penchant for archeology, history, and anthropology. He also has a generally more level-headed outlook than cartoon Martin. And while some of his crass tendencies are still there, they manifest more maturely. In fact, at times, the character almost reads like a cross between Indiana Jones and a proto version of DC's John Constantine.

RELATED: Constantine: 10 Facts To Know About DC’s Hellblazer

Furthermore, whereas the cartoon featured an investigative trio, the comic's various adventures are mostly reserved for Martin and Java -- who, unlike his on-screen counterpart, is mute. Rest assured, Diana is still present in the comics, albeit with one major difference: rather than being Martin's step-sister, she is his fiancée, later his wife.

That's about where the familiar faces stop, however. In Martin Mystère, characters such as M.O.M. and Billy are nowhere to be seen, nor is The Center itself. Rather, Martin's missions are either given to him by the police or the government or simply undertaken of his own volition.

Martin Mystère is also far more mature in its content than the TV show. It's not exactly a Hard-R, Vertigo level title, but it's definitely not aimed at young children either. Rather than Nickelodeon-friendly fantasy violence, which usually consists of chase scenes with narrow escapes, those who read the comic are more likely to see bloody brawls and people being gunned down. While the supernatural element is still present and Martin still finds himself pitted against various ghouls and monsters, he also frequently has to deal with ruthless, gun-toting Men in Black.

Additionally, the show's portrayal of romance never really went beyond schoolyard crushes and cheap (frequently rebutted) pick-up lines. Meanwhile, the comic is much more explicitly risqué in this respect, which is to be expected, given its characters are much older. In fact, there's even a fair bit of nudity in the comic. To be fair, that sort of thing is considered more socially acceptable over in Italy than it is in the States. Nevertheless, it's certainly not something you're going to see in a children's cartoon, and thus underscores just how different the show and comic are from one another.

NEXT: 10 Cartoon Network Shows That Ended Too Soon

Martin Mystery was an interesting show that a good amount of people look back on fondly, and understandably so. However, the sheer disparity between it and its source material is rather interesting in and of itself. There's honestly a case to be made that Martin Mystery is the poster child for the term "loose adaptation." So, if you're a part of the group waiting for the cartoon to return to screens in some form or fashion and need something to hold you over until then, maybe give Martin Mystère a read and get the full scope of this peculiar franchise.