Zealth, as every other Pokemon, was born from an egg, his parents where of differents species, pokemons often fell in love whit other pokemon from sometimes different species, that was not uncommon, his father was a Haxorus, and his mother of course was a Garchomp.

He was a meat-eating pokemon, his favorite meat was of water type pokemons, like Magikarp and Luvdisc, he didnt like to kill intelligent pokemon, there are a few non sentient pokemon, and he only eated them, he was mostly happy, living in a desert whit his family until he evolved into a Garchomp, then he went on a travel, he was adult now, he wanted to get a new place for himself alone, to train and to become even more powerful, so he traveled, he traveled for weeks.
He eventually reached Kanto, thats what the humans called that place anyways, that region, he wanted to be away from any city, so he went to live in Cerulean Cave, it was a really quiet place, and there where lots of powerful pokemon to battle with, and plenty of food. So he settled there temporally.

He was happy to be in a quiet place, he was a really powerful pokemon, and he knew he wasnt going to be bothered by any other pokemon, sometimes he get into fights to train and gain experience, and he eventually decided to start exploring Cerulean Cave, he was just close to the exit, and there was a river outside, he made a little place to sleep, he started to get further into the cave, even further than he ever has traveled into, he had a feeling that something was watching him, but he just keep going further into the cave, it was not too dark for him.

"This place is really quiet, i wonder if there is some other pokemon like me here, someone who would be a real challenge to train whit" He thought.

'You are right, this is why i moved here into this cave, i enjoy the relaxing and quiet environment from this place... and welcome by the way'

The dragon jumped a feet into the air startled "WHAT?! who's there?" He turned around and didnt found anyone, and that voice has come like it was just next to him, he realized after a second that the voice actually was in his head, like it... "A psychic type... where are you?!"

"I apologize for startle you, and im right here."

Zealth turned around and he saw the strangest pokemon he had ever seen, it was his same height, but it looked bigger, his tail was purple and the rest of the body was a light grey colour, his form was humanoid, but he didnt look anything like a human, he was the first time Zealth had seen that kind of pokemon.

"Dont worry, i just was exploring this place" he said politely "so... hello, my name is Zealth, i just moved here for a while, i mean, im just close to the entrace of the cave. What's your name? i didnt know any kind of pokemon like you, but if im right, and you are who spoke in my head, you are a Psychic type?"
-"Yes, my name is Mewtwo, im the only one if my kind, im a Psychic type, actually... im a Legendary pokemon, i moved here recently too."

The dragon jaw was hanging open, 'a Legendary pokemon? here in this cave? This cannot be coincidence! this was an unique chance to battle a Legendary, i dont know how strong he is, well, lets give it a try, anyways, this cannot be that difficult...' he thought to himself, he didnt know his thoughts were being readed.

"Well, you are the second Legendary i met! I wanna ask you something... Can we have a fight? I mean as a training of course... When i was a Gible i met Zygarde back in Kalos, and since i met him i always wanted to battle a Legendary!" He practically bounced in place excited. Mewtwo raised looked at Zealth doubtfully and shrugged.

"Okay, if you wish to have a fight, i dont see the problem, let this be a lesson for you..." Mewtwo grinned to Zealth and they both moved into place 15 feet from the other, Mewtwo spoke in Zealth mind -'The rules are simple, fight until you cannot fight or until or until one of us surrenders' Zealth nodded and started running towards Mewtwo, who stood in place, whit his eyes closed and his arms crossed, he tried to use Crunch on Mewtwo, he knew that if he was a Psychic, it was the better he could do to defeat him fast, Zealth was fast, really fast, in 1 and a half second he reached Mewtwo, but when he was about to attack, he simply stopped, he couldn't move, he struggled against the psych attack but it was no point to try to get free, he could't even close his jaws, he started to hyperventilate, he could't even talk. Suddenly after half minute he was throw back and into the cave side mighty force, his back hitting the cave really fast.

'nice try, but im not that easy to get' Mewtwo spoke into the dragon's head.

The Garchomp growled and started to get up, wincing and trying to ignore the pain of having one of his ribs cracked, he looked at Mewtwo who was grinning at him and started to run towards him again, but this time whit a different idea, he didnt get too close, he stoped 10 feet from him and a sandstorm started to form in the cave, the Dragon type digged under the ground at a incredible speed and made his wat to the place Mewtwo was standing over, he was about to break trough the surface and use Crunch again, but when he tried to dig to surface, something stopped him, he tried whit his claws to dig trough but it was solid, the ground above him had become as solid as the hardest stone, he tried again and again, until he just gave up and tried to get away from there underground, from where he dig before, his eyes widened as something catched his tail and started to pull him towards the place he tried to dig trough, he was scared, he couldn't hold of anything, he tried to get hold of something but it was all dirt, so he got pulled in front of Mewtwo, Zealth was hanging upside down, he struggled trying to attack him, he tried to use his ultimate attack, he knew it was the only chance to get free and maybe do something about the battle.

When he tried to use Outrage, his ultimate and most powerful attack, Mewtwo let him go, and Zealth simply fell to the floor, facefirst, and then he started to feel a pressure in his back, he tried to resist and the force started to get stronger and started to get hard to breathe, the pain was getting worse, whit his last bit of energy he managed to say -"I s-surrender, p-please let me go..." and then the beaten Dragon type's vision turned black. Mewtwo looked at him whit an apologetic look 'you are a strong pokemon, but you have to learn that fighting a Legendary is not that simple, nice try' Mewtwo moved close to him and put his hand on Zealth's back, wich started to glow pink...

Author's Note

Hello, this is the first story i write in all my life, and this isn't my main lenguaje, i will try to improve everything whit time and practice, i hope you enjoy the short and easy to win battle where Mewtwo played a moment whit my Pokemon oc :3 The story is gonna get into the Equestria side in the near future, dont worry, this is like a intro to show some of my ideas, im sure you know what Mewtwo is going to do. Please, let me know my mistakes and i will try to correct everything.