Mew three isn't a Pokemon just a fake made by a fan
In sapphire you cant catch it without events or cheats:-)
There is no Pokemon called Mew3 if you saw it on YouTube it was a hack.
get cheats on a actionreplay.
you can't
in Pokemon yellow, blue, red, fire red, and leaf green you can find mew-two in cerulean cave after you have beten the game, but for mew at the moment you can not get it without cheats...
no you must use cheats because mew hasn't been relaesed in America
No, you need to go to a Pokemon Event if you want a Mew without using Cheats or Action Replays.
no you cant
you trade for it from emerald.
No, you cannot.
transfer from emerald
It is not possible to catch Mew is Pokémon Emerald version without using cheats. The only way to get it would be to trade.