Mine was a plusle in Sapphire. I was looking for electrike on that route under the bike path, and I came across the plusle. I missed the shiny anim., and my sound wasn't on, but something looked a bit odd about it. I caught it, and am glad I did.
My first was a Larvitar in FireRed. Very lucky concidering how low the chanced of finding a Larvitar in that are are. I could have easily ended up with a shiny ratata!
Hmm, well I ran into a shiny Weezing in my FireRed version, but I had no pokeballs except my master ball (which I SO should have used), so I beat it. I don't like, go shiny hunting (well, maybe sometimes), but a few weeks ago I was chaining growlithes so it would be easier to train a marill in attack, and I ran into a shiny one. I forgot what nature it was, but I remember it wasn't bad.
Well, my first ever shiny was a Rhyhorn in FireRed in the safari zone. By then I never heard of shinies and I thought all pokemon had a small chance of being red (like the gyarados). Now I have a shiny Shelgon traded to me by someone on this forum. I personally don't go hunting for shinies because I have things like homework and bass practice to do.
mine was a blue ralts when i found it i had never heard of shinies and i told to my brother:hey i caught a blue ralts. and then he said: yeah right!and i caught a red one...after a few days i reset the game and i lost it.