Don't use it on Rayquza save it until you see a blue or red Pokemon that runs away they won't appear until you defeat the elite four because the Pokemon run away if they escape there pokeball.
a master ball!!!
you have to cheat for it and use a master ball !
you have to put him to sleep then use a ultra ball or master ball
you can use master ball in caught the groudon
you don't get the master ball from may in emerald, you get it in the team aqua/magma hideout in lilycove. that is the only way to get a master ball , unless you win the loto ticket drawing or use an actionreplay or gameshark.
i would prefer giratina or if you have the regis from ruby,sapphire or emerald i prefer regigigas
You can't (unless you use cheats).
just weaken it and use a master ball.
You should use a master ball.
You Can Use A Cheat That Lets You Walk Through walls and you can walk over to the master ball
birth island you meet deoxys on level 30 use master ball or a ultra ball
to catch raquaza easily on emerald, use the master ball at the start of the battle... and you're done!