Where is Bulbasaur in Pokemon Pearl?

Actually a ew days ago my boyfriend was playing Pokemon Pearl and I just beat the elite 4 for him and he was exploring the survival area and he found a Baulbasaur in the grass area, and no he does not have anything added on to his ds. I read about this and everyone was saying its impossible, but i have seen it with ym own eyes it is possible!

You will have to migrate one from FireRed, LeafGreen.

You can see it in the pal park. you could migrate from firered leafgreen. or you could go to ther survival area, and walk around till ya see it