I've seen this commercial every now and then on National Geographic channel, that says birds evolved from dinosaurs and that whales were once land mammals. Yeah....for some crazy reason, one of the creatures, just out of the blue, decided to jump the water and magically turn its legs into fins. The rest saw this, thought it was way cool and jumped in too! Of course some didn't like it, but found that if they went back to land, their legs didn't come back so they were stuck with fins forever.