The ability to turn something into shit. Includes, but not limited to: breaking an object or device, unable to successfully complete a process or routine, or generally F*ing something up.
John: Will borrowed my phone just to give it back to me with a broken screen.
Mike: Will is such a stomach.
The worst organ in the body, one that is intent on bringing you as much pain and nausea as possible.
1.) Kurt Cobain was pained by his stomach to the point where he had to force himself to eat
2.) "My stomach is evil"
"yeah, I get nauseous whenever I eat."