planet Butbutbut. They evolved one day when one ordinary Pig thought, I’m sick of waddling around in the mud! Why don’t I… fly!? He immediately sprouted wings and started zipping around, flipping off birds, and suddenly remembered that he couldn’t land. Very improbably, he found a Mattress that had suddenly popped in from Sqornshellus Zeta, and thus survived to pass this new gene on to his descendants.