Flapsack

The flapsack is the part of the more evolved humans that comes out of where the belly-button is usually located on lesser humans. On the more highly evolved humans, what they do is stick they're index finger into what looks like the belly button hole and pull and a large flap of skin comes out. It can be stretched through out time much like any part of the Human epidermis. Some people can hold up to 23 items in their flapsack. Also the flapsack can absorb data and deduce answers due to its seperate brain, although it is not always fully correct data because the brain is not as evolved as the regular human brain. Horrible things like this occuring through natural selection are usually attributed to the evil exploits of Spider-man.
Flapsack also has another meaning, lesser known but just as incredible. If you ejaculate in excess of 75 times within 24 hours it is very possible your testicles will retract into your body forever, leaving you with nothing but a flappy wrinkly bit of skin where they used to be. This can be stretched to incredible size with some practice, and there are stories of people holding up to 76 items in a testicular flapsack. Expert flapsackologists have obsereved people doing unbelieveable things with their flapsack, cooking rice, making toast, taking a bath, trapping mammals such as camels and rabid dogs in them, even living in them. People have even suffocated in their own flapsack.