Yes you can : You can catch it in the safari zone in the rocky beach area : But you have to add 17 rocks and 13 grassy items : I'm not sure but I think you have to wait 100 days too : Hope this helped
In case You need gible you need to beat the pokemon league and get the N. Pokedex. When you have it you need to wait at least 70 days! (Don't worry you can change the time to 70 days on your ds) But I have no idea what items. He is at rocky beach! Hopes this works!
It would be a whole lot easier to just go to the freaking safari, go to rocky beach, put in the stuff that other guy said too and just set your DS for 100 days later but it's still hard to catch
You
Go to safari zone and wait there 9 days . After go in the poke market and wait there 3 days .then catch mewtwo and suicuine (in the order).finally your mother will give you gible