Doh is Homer Simpson's signature catchphrase from the long-running animated series The Simpsons, voiced by Dan Castellaneta. The groan became shorthand for Homer's frequent blunders and self-inflicted mishaps, repeated across decades of episodes until audiences could recognise the joke from the sound alone. As clips, compilations and reaction videos spread online, individual doh recordings began circulating as short reaction sounds for fails and mistakes. It endures because it is brief, expressive and universally understood, needing no dialogue or context to signal that something has just gone wrong.