A shiny Dragonite? Wow, lucky you. Have you checked its stats and confirmed that it's not hacked? I mean, it could be. Either that, it's most likely cloned, and somebody just wanted to surprise someone by giving it away. Haha.
Shiny Regice... I think I have you all beat ;)
Now that I guess there's hacking involved.. someone gave me a shiny Elgeyem with a Masterball. I suppose it could be just a random act of ridiculous kindness, but I seriously find that whole thing hard to believe