Liquid ASS is described as smelling like a fine combination of "butt crack, kind of a sewer smell with a hint of dead animal." It is arguably the worst smell in the world. High school prankster Allen Wittman invented it man years ago from ingredients in his chemistry set. Now it's used by the US military in war simulations to get medics used to the smell of a torn intestine with wasting spilling into the abdominal cavity. 99% Invisible tells the story of Liquid ASS and it's new application to help save lives.
You can also buy your own bottle for $10 on Amazon.