Capturing Mewtwo is optional, but recommended.
After you have defeated the Elite Four, it is possible to visit the Seven Island (I think they're called the Sevii Islands) via boat from Cinnabar Island.
Have it traded to you from a Firered/Leafgreen.
get every Pokemon in the game then go to mystery cave and catch it
Mew Mew2 Zapdos Moltres and Articuno
after you beat the Pokemon league go back to where you battled misty and to your left there is a Pokemon ranger guarding a cave then you talk to him and he will let you in
You can't.
trade or capture
the Pokemon are pigey, mew2 first of all there are more than that and second pigey is not lengendary
MewTwo can be found and caught in Cerulean Cave. Hint save before you battle him and if you fail you can try again.
You must capture Mew on Emerald and trade it to FireRed.
It is in mt. ember.
Nothing except capture them.
well you passed it when the credits go up and you can go get the legendary mew2 and the rest is the bonus storyline that's it