You have to soft reset and have lots of luck!
i have a mewtwo here and it isn't really hard to catch.... rayquaza is really hard to get but you can see it on your way... pikachu, i guess, is the hardest because we can't catch it by only one try...
I am pretty sure this works the same way as other shiny Pokemon (approx. 1 out of a million chance.) I don't knnow for sure. However you do get to catch Mewtwo, i know because i did using only (surprisingly) 2 ultra balls(<sounds wrong<)
Nature has no factor of whether or not you find a shiny Pokemon the nature will change depending on the Pokemon of course now if your catching a shiny mewthwo then everytime you catch a shiny mewtwo it should have different natures granted it's possible to have one of the mewtwo's to get that same nature of the first one or the others.
I can't tell you the code for the shiny mewtwo because you did not say what game this is for. You can try the Pokemon Modifier with the Shiny code.
No. Actually, it means you are very lucky. What you have there is a shiny Mewtwo. Shiny Pokemon are incredibly rare: there's a 1 in 8192 chance of finding one. The fact that your Mewtwo is shiny is certainly incredible.
You can't catch Mewtwo in Pokemon Diamond and pearl and also platinum. But you can catch Mewtwo in heartgold and soul silver
how do you catch a mewtwo on Pokemon platinum
you can't catch mewtwo he is too tough to catch but if you don't listen to me you are a NOOB
You catch Mewtwo in the Cerulean Cave. The cave is very long and puzzling and will require much searching to find him. Mewtwo is located in the very end of the maze.
All you have to do Is save when you get to him and soft reset until shiny
By cheating.
Yes. It is completely possible to catch Mewtwo with an ultra ball.