For a number of years, the"X-Men" were so popular that most of Marvel's highest-selling titles were either "X-Men" or related to "X-Men" in some way ("X-Factor,""Wolverine," "New Mutants"/"X-Force," etc.). It got to the point when characters began to associate with "X-Men" even if they had no connection at all. "Spider-Man" promoted itself as Marvel's most popular non-mutant. A new "Namor" ongoing series launched by touting him as Marvel's first mutant. Being a mutant was the thing to be for many years.

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In recent years, things have calmed down a bit, and in fact some characters that were declared to be mutants (like Squirrel Girl, Toro, Scarlet Witch and Quicksilver) have turned out tonot be mutants. However, there are still plenty of mutants out there that people still don't know about, especially the much rarer alien mutants. Here, then, are 15 Marvel characters that you probably didn't know were mutants, ranked in terms of how surprising it is that they are mutants.

15 MOST OF THE GREAT LAKES AVENGERS

After theAvengers were seemingly killed during Onslaught, the Great Lakes Avengers, a not-quite-affiliated team thatHawkeye tried to whip into fighting shape, decided that they needed to change their name. So they picked the Lightning Rods in honor of the new group of heroes known as the Thunderbolts. Of course, they felt silly when it turned out that the Thunderbolts were criminals. They debated what to call themselves until they realized something important: they were all mutants! Therefore, they called themselves the Great Lakes X-Men for a while before going back to the being the Great Lakes Avengers.

The mutant members of the team are Mister Immortal (who cannot be killed), Doorman (who can teleport people through his body - he died and became a new agent of Death), Flatman (who can stretch) and Big Bertha (who can dramatically increase her size). Squirrel Girl used to be a mutant member of the team, as well, but she recently discovered that she wasn't a mutant. They recently added a new member, Good Boy, who may or may not be a mutant, as well. Since they literally called themselves X-Men at one point, they're the least surprising mutants.

14 DEVIL DINOSAUR

Devil Dinosaur was actually part of a mutant team, it just wasn't any of the popular mutant teams.Devil Dinosaur, and his best buddy, Moon Boy, were part of the team of mutant outcasts known as the Fallen Angels. That team was formed when Sunspot accidentally nearly killed Cannonball during training. He fled to New York and Warlock followed him.Madrox and Siryn were sent to keep an eye on them and they all ended up caught up in a sort of gang of young mutants led by the Vanisher. They broke free of the Vanisher and formed their own team (but mostly just hung out).

Devil Dinosaur is a mutant due to his intelligence, which is close to that of a human, and possibly his whole red look. Interestingly, in his current series, "Moon Girl and Devil Dinosaur," he's paired with an Inhuman. See, this shows that mutants and Inhumans can get along!

13 KRAVEN THE HUNTER (#3)

A few years after Kraven the Hunter took his own life in the classic"Spider-Man" storyline, "Kraven's Last Hunt," his son took over the family business, as it were, as the Grim Hunter. For some reason, though, the Grim Hunter was not enough for the "Spider-Man" titles, so they then introduced Kraven'sother son, Alyosha Kravinoff. Alyosha's mother was a mutant and Alyosha had the mutant power to be basically super-strong, fast and agile like his father. He essentially had the same powers as his dad, only his came from being a mutant while his father got his from potions.

Amusingly enough, Aloysha went through a period where he decided to become involved in producing films. This led to the mini-series, "Get Kraven." When that was finished, Aloysha went crazy, but eventually he was replaced when his father was resurrected. His father and his sister hunted Aloysha down and killed him.

12 SILHOUETTE

Silhouette and her brother, Midnight's Fire, were characters introduced in the pages of "New Warriors." They were the daughter and son of Andrew Chord, who was the former guardian of Dwayne Taylor. She, her brother and Dwayne were vigilantes together on the streets of New York. She and Dwayne began a romantic relationship. Tragedy struck, though, when she was shot in a police sting gone wrong. She was paralyzed from the waist down. Her brother became a villain and Dwayne became the superhero known as Night Thrasher.

Silhouette trained herself to fight without the use of her legs, using braces to allow herself to get into battle, along with her mutant ability to teleport and also become a living shadow (both were essentially the same powers thatNightcrawler has). She and Night Thrasher became a couple again and she joined the New Warriors. She and Dwayne eventually broke up and she started dating his half-brother, Bandit. She was part of the superhero resistance duringCivil War.

11 WHIRLWIND

One of the most resilient villains in Marvel history, Whirlwind has managed to stick around for decades without being killed, which is a pretty impressive resume for a supervillain. He hits that very small sweet spot in that his mutant ability to spin and create wind vortexes makes him just powerful enough to be worth consideration, yet not powerful enough that he can fight a bunch of superheroes on his own. This has made him the perfect filler supervillain, although efforts have been made over the years to upgrade him (mostly by giving him lots of blades).

Whirlwind is probably the closest that you can come to an arch-rival of theWasp. He fought her andGiant-Man as the Human Top before taking on the identity of her chauffeur. He grew obsessed with her and even now he remains creepily interested in her. He's one of the villains who have have served on the most incarnations of the Masters of Evil supervillain team.

10 SKEIN

Skein is an excellent example of how minor characters can be developed by later writers into more interesting versions of their original selves (that's basically the calling card of the "Thunderbolts" as a title in general). Skein was the supervillain known as Gypsy Moth, who had strong telekinetic abilities, but she chose to only use her telekinesis on "soft" things like fabric. This way, she could unweave any sort of fabric and then reweave it almost instantly. While a villain ofSpider-Woman in Los Angeles, she formed her own sort of sex cult.

After a number of years of being a reliable piece of cannon fodder, she abruptly decided to join up with theThunderbolts. She changed her name to Skein and fought alongside the good guys for a few years, although it was always clear that she was doing it more because it entertained her than out of any sense of morality. More recently, she has returned to a life of crime, while keeping the Skein name. She famously unraveled Spider-Man's costume in the first issue of "Amazing Spider-Man" following "Superior Spider-Man."

9 BUSHWACKER

Bushwacker is a weird one for this list, as he made his debut early in Ann Nocenti and John Romita Jr.'s"Daredevil" run as a killer of mutants. He was a former priest who began to work for the C.I.A. and it was while with the C.I.A. that his body was cybernetically altered so that he could transform his arm into a weapon. He hunted down mutants, claiming that he was paid a lot of money to kill them, but it appeared that it had more to do with some crazed obsession on his part than anything financial.

He became a recurring villain in "Daredevil" and some other titles, like"Punisher" and "Nomad." However, in the David Lapham miniseries, "Daredevil vs. Punisher," Bushwacker made a shocking confession. He revealed that the whole "C.I.A. gave me cybernetic implants" story was a lie and that he was actually a mutant himself! He apparently just took self-hating to a whole other level.

8 SHRIEK

Shriek debuted as part of the popular crossover event "Maximum Carnage," as the "mother" toCarnage's "father" in their growing "family" of sociopathic killers that formed the basis of that event, which saw Spider-Man being forced to team up with his former foe, Venom, to stop the even worse criminals. This was an interesting period where Venom had grown so popular that Marvel decided to invent someone so evil thatVenom would look like a hero in comparison. So that way they could give Venom his own book and still have a symbiote villain.

It is unclear which of Shriek's powers are her natural, mutant ones. She has the ability to sense people's dark emotions and also to know how to fester those dark feelings. She has sound-based powers that let her create concussive blasts or use her abilities as a sonic scream meant to disorient and drive people mad. Some of her powers kicked in when she was trapped in Cloak's darkforce dimension. Which ones kicked in then are unclear, but what is clear is that she's one of the few purely evil villains out there.

7 MENTALLO

Like Whirlwind, Mentallo is one of those rare villains that has survived mostly unscathed for 50 years now (okay, he was once presumed dead a few years back, but that was very brief!), debuting in an earlyS.H.I.E.L.D. story. Mentallo is also one of the few mutant telepaths on Marvel's Earth that is not connected with the X-Men in any way, shape or form. Mentallo often teamed up with his friend and colleague, the Fixer, to wage war on S.H.I.E.L.D. as well as take part in various other criminal enterprises.

The Fixer, though, eventually tried to reform as a member of the Thunderbolts. Mentallo, though, kept up his villainy through and through. He started off as a member of S.H.I.E.L.D., working for their ESP program before he tried to take over S.H.I.E.L.D. using his telepathy. Rebuffed, he joined up withHydra and A.I.M. instead. He has even become a fairly high-ranking member of A.I.M. in recent years.

6 MADAME WEB

Cassandra Webb was born a mutant with tremendous telepathic and precognitive powers. However, she was also born paralyzed and blind. Over time, things got even worse for her physically, as she developed myasthenia gravis, so her husband built her a life support system that she had to remain attached to. She became involved with Spider-Man, using her powers to fill him in on crimes that she could not physically deal with herself. She also revealed that she knew his secret identity due to her telepathy. She was one of the first people to learn Spider-Man's identity (and not die right after discovering it, that is).

Over time, she regained her vitality but then lost it again. During the "Grim Hunt" storyline, she was murdered and passed on her abilities to Julia Carpenter. It is unclear how she was able to pass along abilities that were hers genetically, but hey, this is comics. She was recently resurrected as part of the"Clone Conspiracy."