I remember seeing a friend of mine bred two different Pokemon to get a starter. As the theory goes, he was playing sapphire and showed me how to get a Mudkip from a Wingull and a Marill (based on memory). It was weird and I don't know if he hacked his game in order to get a baby Mudkip. I never got a Mudkip from the two Pokemon when I did it.
What happened?