Beat the elite 4 and after go to the cave in cerulean city.
i have a mewtwo here and it isn't really hard to catch.... rayquaza is really hard to get but you can see it on your way... pikachu, i guess, is the hardest because we can't catch it by only one try...
The only way to catch either one of them would be to transfer from an other game, since they aren't found in Pokemon pearl.
The best way would be to catch Mewtwo with a MasterBall. However, you can also catch it with Ultra Balls, but that will cost you a lot of them. Mewtwo is a psychic pokémon, so it's weak (2x) against bug, dark and ghost types. It's highly recommended to breed a Rattata so it learns the move Endeavor. After Mewtwo has 1 hp left, due to this attack you can put it to sleep, freeze it or paralyze it.
there is no mew island (i think) u need 2 go to cerluean cave(located in cerluean city) after getting mewtwo(it will be at lvl 70(mewtwo)mew is at lvl 62 or 63 to get mew walk around but u have to catch mewtwo first that's the only way! use a masterball or pokeball, mewtwo must b asleep for pokeballs
Easily Rayquaza. One you defeat all 16 gyms you can find Mewtwo in the same cave north of cerulean that he was in in the first gen games. To get Rayquaza you must beat all 16 gyms, then beat Red on Mt. Silver, then talk to Mr. Pokemon on Rte 30 to get the Red or Blue orb (depending on whether you are playing HG or SS). Then go to the embedded cave south of the safari zone and catch either Groudon (SS) or Kyogre (HG). Then you have to get whichever of those you didn't catch from another game (only the Groudon and Kyogre from HGSS will work for this) until you have both of them and then go back to the embedded cave, where you will find Rayquaza. Now if you are talking about which is tougher to beat/catch, again Rayquaza. Mewtwo only knows 1 move that can damage you, Psycho Cut. If you bring a Dark type Pokemon there is no way Mewtwo can hurt you.
The fastest way on HeartGold or SoulSilver would be to go into the Safari Zone and find it there.
the quickest way of finding it is using file function
With a master ball.
The only sure way to instantly catch any Pokemon is with a Master Ball.
catch a high level larvitar lol
i have a mewtwo here and it isn't really hard to catch.... rayquaza is really hard to get but you can see it on your way... pikachu, i guess, is the hardest because we can't catch it by only one try...
MewTwo is really strong. Try to get your hands on a master ball, as that's the only way people i've known have done it
Airplane is the quickest.
You cannot catch more than one Mewtwo. The only way to have more than one is through trading with someone else with the game.
you have to weaken it to like no life and then you have to paralyze it and use ultra balls
ANSWER 1:Mewtwo appears only in Fire Red and Leaf Green. You can catch him in either of those games and then trade him to Pokemon Ruby.sorry mate its impossible only way is to trade like this guy said (: (: (: (: (: (: (:ANSWER 2:I regret to tell you that you cannot catch Mewtwo in Ruby. You can only catch Mewtwo in FireRed or LeafGreen. (You can use cheats to get it but it wouldn't be as fun).Mewtwo is at Level 70 in LeafGreen and FireRed so use an Ultra Ball/Timer Ball/Master Ball.If you need/want a Mewtwo you can trade Mewtwo into your Ruby/Sapphire/Emerald Game.
The only way to get a Mewtwo in Pokmeon Crystal is to trade with a copy of Red, Blue, or Yellow through the Time Machine in Pokemon Centers.