The line comes from Bill, a character in The Thunderlizards, the animated segment built around dinosaurs hunting two hapless human cavemen. Bill and his partner were constantly caught in slapstick chases and injuries, which made his pained lines easy to lift out of context. As short cartoon quotes began circulating on soundboards and in edited videos, this plea stood out because it works without any setup. It now survives mainly as a reaction clip for pain, exhaustion and comic suffering rather than as a reference to a specific episode.