Many years ago, back when Diamond and Pearl came out, I was playing Pearl and was attempting to capture Giratina. I was new to Pokemon at the time and I sucked at capturing legendaries. I brought Giratina to red health and proceeded to try many different Poke balls (you name it: Ultra balls, Great balls, Dusk balls, and even Timer balls. I was saving my Masterball in case it were necessary for other legends). Out of frustration, I then threw a Poke ball at it and said to myself, "If I catch this thing, I'll be so surprised."
One. Two. Three. Click!
"Oh my god! I caught Giratina in a Poke Ball!"
It had a great nature, too (jolly). Sadly, I got rid of it recently because I didn't train it properly. :C