Real Pie is real pie, I mean it, no bombs, no poison, just fresh baked, sweet and delicious. It is usually fed to regular humans or fat people who eat it a lot. It can also be baked savoury. If you were looking for Pi, as in 3.14, then there's a "reliable" source called school.
Real pie can be abused by putting a bomb, poison or something dangerous. It will be turned into a pie called pie. So watch out!