I'll have you know that I'm a legendary beast-master!

[Munchlax11]

I remember back when I was playing Ruby, before I inflicted damage or status on groudon, I just tossed a pokeball at him and then it clicked and I caught him. I was so excited when it happened. :P

 

[Altairis]

Zekrom in White was the first non-Master ball legendary that I caught under 15 minutes. I have horrible luck!

 

[fishyfins]

Mewtwo in pokemon red, back in the day. just wondered what would happen if i just threw a regualar pokeball right away when the battle started. Well ill be damned, it caught the bugger!

 

[Dark_Illusion]

Cobalion, unsure of the catch rate, but Ultra Balls were the ball of choice. Only took a couple. That moment made me happy because I was prepared to turn my game off and on until I got him with Ultra Balls. Lol

 

[Altair1]

My fastest catch was Tornadus in Black, quick ball first encounter.
I also caught a Mewtwo with a master ball in FireRed.