Developing a very painful stomach ache after ingesting something you don't typically eat. Refers to the episode of Always Sunny in Philadelphia when Frank is stranded in the woods, hungry and fatigued, and decides to eat a decaying crow. Later he wakes up in the middle of the night groaning of stomach pains. When Dennis and Dee ask what's wrong Frank replies "I ate the crow".
Dude, I ate the crow, that Afghan shit we ate fucked my stomach up.