well you can do anything like battle the elite four, battle the seven islands to get more cash, or maybe just train your pokemon.
You can catch MEWTWO ,not Mewto, at the end of Cerulean cave
action replay
no
you can't catch him on sapphire but you can on emerald.
with a master ball
I think that's all you can do in the game
yes
Yes,its level is 70.
That's impossible.
Unfortuenetly u cant catch mewto on emerald only on fire red.green and dimond and pearl! SORRY SUCKERS!!!!!!!
you can still go to cerulean cave to catch it like in firered and leafgreen
you cant do anything because you did everything