you have to beat the elite four. and, you have to rescue Lorelei on four island. And inside the cave lies... MEWTWO!
Cerulean Cave
Cerulean Cave
No
Cerulean cave located near cerulean city.
mewtwo is in cerulean cave
Cerulean cave
inside cerulean cave near cerulean city.
It is in Cerulean Cave. It is on the bottom floor of the cave! :P
You can find ditto in cerulean cave.
In Cerulean cave in Pokemon firered and leafgreen
You can find Mewtwo in the Cerulean Cave.
After you beat the Elite Four.