The biology of Pokémon is pretty bizarre if you stop to think about it. There's lizards with burning tails, giant turtles with cannons in their backs, and yellow mice with batteries in their cheeks. That's not even getting into stuff like Magnemite or Muk which are inanimate objects somehow come to life. But of all the Poké-universe's strange inhabitants, Mewtwo may be among the most curious anatomy-wise. It is literally a mutant. That's where its name comes from in Japanese. Mewtwo sounds very similar to the Japanese word for mutant. And it is that very nature as a mutant that separates Mewtwo from not just its fellow Pokémon, but many real world animals as well.
The thing that must be understood about Mewtwo is that it is a man-made creature, the result of genetic modification and manipulation. Based off the DNA of the elusive Mew, scientists messed with its genome to create the world's most powerful Pokémon. To their horror, they succeeded. Mewtwo's greatest attribute may be its powerful brain. This pocket monster has genius-level intelligence, immense psychic powers, and a savage heart devoid of compassion. But that mighty brain has left other areas of Mewtwo's body underdeveloped, as this list will show.
Mewtwo is a genetic anomaly, and it shows in its anatomy. There are even connections to the real world science of cloning in some of the flavor text. But the mad science that created this monster left it with a body unlike any other Pokémon.
These are the 20 Craziest Things About Mewtwo's Anatomy
20 It Has No Gender
The question of whether Mewtwo is a boy or a girl is a moot one. It's neither. Mewtwo has no biological gender. This is a trait that carries over from its DNA donor Mew. As the common genetic ancestor of all Pokémon, Mew is also genderless to better allow it to mutate into other species. How a genderless Pokémon reproduces is probably best left to the imagination.
Despite Mewtwo having no biological gender though, it's been shown with both male and female voices. Fans of Pokémon The First Movie will remember that Mewtwo communicated with a deep, masculine voice. Meanwhile another Mewtwo in the Best Wishes anime used a more feminine voice. It seems to choose which gender to present as.
19 Big Brain, Weak Body
Much of Mewtwo's great strength comes from its remarkable brain. That is the seat of its psychic power. Its original sprite from Red & Blue even emphasized its big head to show this. But Mewtwo's immense mental ability has a downside. With all the energy going to its head, its body is physically weak. This is why Mewtwo will avoid physically moving as much as to possible, to conserve more energy.
Yeah, despite its thick thighs, it's not a runner. When it does need to move, it will often use teleportation or telekinesis for the same reason. Of course, Mewtwo's psychic abilities move it around faster than its legs ever could, so maybe it's not really much of a downside.
18 In The Games, Mew Is Its Mommy
How Mewtwo was created differs depending on which version of the story you read. In the original Pokémon Red & Blue games, the scientific logs on Cinnabar Island say that Mewtwo began life as a normal Mew embryo. The scientists had managed to capture a live Mew in South America and altered the DNA of one of its eggs. Then, the Mew gave birth to Mewtwo as normal.
They tampered with its DNA some more after that. While disturbing in context, this is how actual cloning is done in the real world. Dolly the Sheep, the first cloned animal, was created almost exactly the same way. Except Dolly's DNA was just the same as her mother's, not modified to create a horrible psychic monster.
17 It Can Only Be Created In A Lab
Like many real world genetic hybrids, Mewtwo is unable to reproduce. There aren't going to be any baby Mewtwos running around. Or floating around, we guess. This is due to its nature as Mew's modified clone, and the reason why it has no evolution. Nature would not have created such a Pokémon.
Its already at the peak of its biology and growth. Limiting the monster in this way also may have been a precaution by Mewtwo's creators. One Mewtwo is dangerous enough, a litter would be catastrophic. Nevertheless, it explains why Mewtwo is so rare and why there have been so few. Most versions of Pokémon only have one. In the anime, only three Mewtwos have appeared.
16 The Creature In Cerulean Cave
Many gamers remember their first encounter with Mewtwo. They had become Champion and went hunting for this urban legend in the Cerulean Cave. But its choice of hiding place is telling, and with evidence from other stories, might suggest something interesting. Mewtwo may have a sensitivity to sunlight.
Both the games and the anime show it having a preference for caves as dwellings. The few times it has appeared in the city, it's always been during the night. Even Pokémon The First Movie took place entirely during a dark, stormy night at sea. While this isn't enough to declare Mewtwo as nocturnal or anything, it does show it having a preference for darkness.
15 Mega-Evolutions Times Two
Mega-Evolutions were a cool new idea introduced in Pokémon X & Y. Temporary power boosts for fully evolved Pokémon shown as new "Mega" Forms. Mewtwo, as the world's strongest Pokémon, of course got one. But of the 48 Mega-Evolutions, it was special. It is one of only two Pokémon that has two Mega-Evolutions.
As if Mewtwo weren't already powerful enough, both of these new forms greatly enhance its strength. We'll chalk it up to its Mew heritage for Mewtwo's, uh, mutability in getting two Mega-Evolutions. Mew is at the root of all Pokémon DNA after all. That doesn't explain how the other Pokémon with two Mega-forms, Charizard, has them. We're guessing popularity.
14 The Strength Of Mega Mewtwo X
Mentally, Mewtwo is unstoppable. Physically, it's nothing to write home about. But its X Mega-Evolution turn its weak body into a powerhouse. In this form, Mewtwo will use all of its psychic power to augment its muscles. The transformation alters its body into a fighting machine. Its already human-like proportions become even more so.
The Pokédex describes it as having a one-ton grip strength and it can stretch its limbs to use special martial arts. Mega Mewtwo X does have the drawback of diminishing Mewtwo's psychic powers in this form. But given that it already puts telekinetic force into each of its blows, the increased bodily strength makes up for it. The most dangerous combo of brains and brawn.
13 The Speed Of Mega Mewtwo Y
Mewtwo's body is almost detrimental with how big it is. Its brain uses up most of its energy, leaving its physical form pretty weak over all. A smaller form focused on its mental power would suit it better. Lucky for Mewtwo, that's just what its Y Mega-Evolution does. Its body becomes much more compact in this form, shrinking from six feet to four. With this smaller size, its psychic power and speed grows even more powerful.
The Pokédex says Mega Mewtwo Y can crush a skyscraper with a thought. It's more aerodynamic too, turning Mewtwo into a living missile. This emphasis on speed and psychic power are the reasons Masahiro Sakurai chose Mega Mewtwo Y over X for the character's Final Smash in Smash Bros.
12 The Debunked Science Behind Mew And Mewtwo
Pokémon fans who also know their history of Biology have noticed a connection between the duo of Mew and Mewtwo and some debunked science. The relationship between the clone and its original is similar to Recapitulation Theory. In brief, this theory stated that an embryo will go through different stages of its evolution before being born.
Mew has a lot of embryo imagery in its design, being smooth and pink with a long tail often in a transparent sphere. Mewtwo, on the other hand, resembles the fully grown version of the embryonic Mew. Like Mew is the stage it has to go through before becoming itself. Along with Mew's status as common genetic ancestor for Pokémon, all this connects the two to Recapitulation Theory.
11 It Understands Language, But Can't Speak
Unlike many Pokémon, Mewtwo is no simple animal. Its brain is advanced enough to achieve sapience and understand human speech. Yes, Mewtwo is one of the few Pokémon that can speak in human language. Well, sort of. Mewtwo can't physically talk with its mouth. We're unsure it can even call its name like most Pokémon. But it can "speak" via telepathy. It broadcasts its thoughts directly into people's minds.
This "voice" is Mewtwo's primary mode of communication and self-expression. But that's not all. Mewtwo has a genius-level intellect that allows it to, among other things, design a giant castle for itself, build a cloning machine, and contemplate serious philosophical questions. In the most angsty manner possible. Mewtwo's just a moody teenager at heart.
10 Its Cells Are Cancerous
Mewtwo was designed to be the most powerful Pokémon of all time. While most of the danger to others comes from its vast psychic power, its very body is deadly. Its cells are cancerous and if they enter an organism's system, that organism could perish. The Gym Leader Blaine learned this the hard way. He was a member of Team Rocket who worked on Mewtwo's creation in the Pokémon Adventures manga.
During his experimentation on the genetic Pokémon, he was exposed to some of Mewtwo's cells. They infected Blaine's arm and the man himself said they'd eventually end his life. What's more disturbing is that it's implied Mewtwo is willing his cancerous cells to spread as revenge for Blaine's mistreatment.
9 Its Limbs Have Atrophied
The design of Mewtwo's body seems contradictory. While its bottom half has strong legs and a powerful tail, its top half looks almost skeletal. Its arms are as thin as sticks, its chest looks sunken in, and its head resembles a skull. What is the reason for this? Again, it relates to Mewtwo's reliance on its psychic power.
Because it uses telekinesis for much of its movement and interaction with the world, its limbs have atrophied from neglect. Like someone in a coma. Only not entirely in Mewtwo's case. Its legs remain strong from supporting its 300 pound weight and its tail actually helps direct its flight path, so they get regular use. But its puny little arms? The most they do is throw Shadow Balls.
8 Not A Cat
When it comes to real-world analogues, it isn't quite clear what Mewtwo is supposed to be. There's no obvious answer for what sort of animal it relates to. The closest most people can guess is that its some kind of cat. The Pokémon Handbook even describes it as a "ferocious feline." Despite this, Mewtwo is not a cat. You can blame Mew for a lot of this confusion.
It is based on a cat and its feline qualities are much clearer in its design. Even its name, Mew, comes from the sound cats make. Mew was also found in the Amazon Rainforest, home to several species of big cats like Jaguars. Though they have more in common with the savage clone than the gentle Mew.
7 No Trainer Needed
Of Mewtwo's many qualities, domesticated would not be among them. It harbors an intense animosity toward humans due to the experiments that created it. Working for Giovanni probably didn't help. Mewtwo has no time or need for a Trainer. Which makes it all the more impressive that it can Mega-Evolve. Usually a Pokémon needs to be holding a special Mega Stone and have a strong bond with its Trainer before it can Mega-Evolve.
Mewtwo needs neither of those. In the movie Genesect and The Legend Awakened, a Mewtwo evolves into its Y Mega-Evolution seemingly at will. It doesn't even need to be in danger. It does so just to have a race with some bird Pokémon. Which seems like cheating to us but whatever, still impressive.
6 Stronger Than Arceus (The Pokémon God)
As the generations have gone by, Mewtwo has had to relinquish its crown as World's Strongest Pokémon at times. It was the original OP Legendary, but challengers came for its throne. That is until Mega-Evolutions at least. While its regular stats are still overshadowed, Mewtwo's Mega-Evolutions have the highest base stats of any Pokémon at 780.
That outclasses Arceus at 720, and he's the literal God of the Poké-universe. When you're punching above the weight class of the creator of the universe, you know you're in a league all your own. The only Pokémon who comes closest is Mega Rayquaza, who's got Mewtwo tied at 780. It doesn't stop there. Mega Mewtwo X has the base Attack and Mega Mewtwo Y has the highest base Special Attack.
5 Good Thing You Can Heal
Mewtwo's body may be somewhat frail, but that really isn't an issue for it. Among its many abilities is the power to heal and regenerate from wounds. Even the scientists who created it were surprised by this power. The cloning process was taxing on the clone's bodies and often destroyed the test subjects. At one point, it appeared Mewtwo's life signs had flat-lined.
But then, its body began to regenerate. This is yet another gift from its DNA donor Mew. Mew was discovered to have an immortal life force and so its DNA was necessary to create a clone that would survive the process. Once they learned of its healing factor though, the scientists were ecstatic. It was perfect for the world's most powerful Pokémon.
4 Its Mysterious Second Neck
One of the more iconic parts of Mewtwo's anatomy is its second neck. Extending from the base of its skull to the top of its spine, many have wondered what purpose this odd feature serves. Mew doesn't have one. The scientists must have included it for a reason, right? Well, no one really knows what Mewtwo's second neck is for.
No explanation has been given, either in-universe or in the real world. In that absence, fans have made their own guesses. Most seem to think it has something to do with Mewtwo's nervous system. A brain as powerful as it has would require a lot of blood, so the neck might help with that. Or maybe its big brain just needs some extra support.
3 The Mystery Of Mewtwo's Creation
How exactly Mewtwo was created is rather unclear in the Pokémon canon. We know it's a clone of Mew, all the stories are clear about that. But the method of its birth differs between the games and the anime. In the games, Mewtwo was born the normal way. It grew in the womb of a normal Mew after scientists tampered with the DNA of its embryo. Even its birthday, February 6th, is mentioned.
But in the anime, Mewtwo was cloned from a fossilized Mew eyelash. It grew in a tank and scientists meddled with its genetic code as it developed. Fans have argued about which of Mewtwo's origins is the correct one , though the anime version is favored for fitting better with later canon.
2 It Might Have Human DNA
Genetic Modification played a big part in Mewtwo's creation. But how exactly was Mew's original DNA changed? In the Pokémon Adventures manga at least, the scientists added in human DNA to the genetic code. Gym Leader Blaine, a scientist on the project, found their Mew DNA was unfinished. So he added in samples of his own DNA to complete the genetic code.
This, sort of, makes sense. If the Mew DNA came from the fossilized eyelash, then it would have degraded over time. Using another organism to fill the gaps is logical (though using a human instead of a Pokémon isn't). That's what the scientists in Jurassic Park had to do to clone dinosaurs after all. And just like Jurassic Park, it went horribly wrong.
The aim of Team Rocket's Mewtwo project was to create the world's strongest Pokémon. That project succeeded, too well. Mewtwo's immense psychic powers and genius intelligence make it not only dangerous to Pokémon, but to humans as well. It has never willingly submitted to any Trainer or Master. The only way humans have found to control Mewtwo is to suppress its power in some way.
Giovanni understood this, tricking Mewtwo and trapping it in special armor that kept in check. The genetic Pokémon eventually overcame this restraint. Even in the games this holds true. The only guaranteed way to catch Mewtwo is by using a Master Ball, which catches any Pokémon on the first try. Its hatred for humans is just that strong.