Since Mewtwo’s first debut in Pokemon Red, Blue and Yellow, we haven’t seen this elusive and powerful Pokemon appear in other games, outside of the FireRed and LeafGreen remakes, until Pokemon X and Pokemon Y.
In addition to the two legendary Pokemon, Xerneas and Yveltal, that players can catch in Pokemon X and Pokemon Y, Mewtwo is among the legendary Pokemon that everyone can catch in the game, and with the right Mega Stone, players can achieve its Mega Evolution form in battle. Just like in Pokemon Red/Blue/Yellow, catching Mewtwo is not an easy task (unless you have a Master Ball in hand).
Well, if you have the patience and the right PokeBall to catch it, here’s where to catch Mewtwo:
1. After defeating the Elite Four and becoming the Pokemon Champion, go to the Pokemon Village and you will find that the man blocking the cave near the top left corner is no longer there.
2. Go inside the cave and you will find Mewtwo with its back against the door.
3. SAVE RIGHT NOW!
4. Talk to Mewtwo and you will get a cutscene.
5. Be ready to fight it!
Your single worst enemy in this fight is going to be the move Recover. Mewtwo will constantly use it and erase the health you whittle away. Eventually he will run out of PP if you last long enough, but it is quite an annoyance. Try to use something like Thunder Wave early in the fight to get Mewtwo paralyzed, so there is a chance he will not be able to attack on some turns. A move like False Swipe is probably not worth trying here with Mewtwo recovering as often as he is. You may also want to avoid using Poison or Fighting types as Mewtwo will destroy them very easily.
Due to being in a cave, your go-to Poke Ball should be the Dusk Ball as it will give you a 3.5x multiplier. As you get deeper in the battle, you should try and use Timer Balls as it is based on how many turns you have been going for a max of 4x multiplier. This is the ball that eventually caught Mewtwo for me.
As soon as you catch Mewtwo, you will receive a Mewtwonite Item depending what version of game you have.
Congratulations! You just caught Mewtwo!