The exact recording source for this goofy fahhhhh clip is not documented, so it circulates mainly as a standalone reaction sound shared between editors. It builds on the online 'goofy ahh' phrasing used to label something unserious, stretching the final syllable into fahhhhhhhhhhhhhh for extra comic timing. Short video editors pair it with other exaggerated reaction hits, but use it on its own when a single drawn out yell says enough. Its popularity comes from instant recognition, even without any visual context or dialogue to explain the joke.
About this sound
Goofy fahhhhh is a stretched, silly scream sound effect used for funny fails, dumb moments and reaction edits where a character does something ridiculous.
This clip is a long, wobbly vocal yell that starts with a goofy fah sound and drags it out into an exaggerated fahhhhh. The pitch bends and shakes as if someone is slipping, falling or realising a mistake in slow motion. It is not scary or aggressive, it sounds deliberately stupid, which is why it lands as comedy rather than shock. Placed over a blank stare, a bad decision or a clumsy fall, it instantly tells the viewer not to take the moment seriously and turns embarrassment into a punchline.