John: "What are you doing with that empty 2-liter bottle?"
Ethan: "I'm farting into it. I'm making a butt bomb."
Ethan: (BRUBP!!) "Stand back!!"
Ethan places the capped bottle into the fire pit of their camp site and waits. Within seconds, the bottle explodes with a loud THOPP!! It shoots into the air.
An Arab or other terrorist hides explosives in his butt and then tries to blow up a plane, train or government building.
They are going to lock the rest rooms on planes to stop the butt bombers.