It was a Shiny Chansey, from the safari zone in FR/LG. this wasn't on a rom, it was real. That was the first Chansey i ever saw, so I thought it was normal, and somehow I caught it. After my firend told me Chansey were not supposed to be green, and they were rare, I searched up about shiny Pokemon, and that it. Traded it to Diamond, then to HG, then to my White.