Foxes look a lot cuter than they sound.
In movies, foxes are often portrayed as slick characters, capable of conning others with their smooth voices and glossy fur coats. Or else they're seen as adorable balls of fluff, perfect hypothetical pet material. Neither of these images can prepare you for the distinctive fox "scream."
The scream isn't the only sound a fox makes, of course. While their vocalizations aren't quite as varied as the average dog, they can bark, yip, and whimper.
The scream, though, is in a category all its own. Heard most often during breeding season, the sound is so abrasive that it's sometimes mistaken for a human in distress.
As Dan Nosowitz wrote in Popular Science,
The red fox does not have a mellifluous voice; even when it's happy, it mostly sounds like it's being strangled. It would be awkward to teach your young child that the cow goes moo, the frog goes croak, and the fox goes YAAGGAGHHGHHHHHHAHHHH!!!!!
In the video above, a fox plays with a dog in a yard, until the dog scampers back to the house, whereupon the fox lets out a scream in protest. In the video's description, the uploader writes that after the interaction they would regularly "hear that crazy bird-like scream the fox makes."
There's many different way to describe the fox's odd sounds. If you're Norwegian comedy duo with a viral video under your belt, you might hypothesize something more along the lines of: jacha-chacha-chacha-yow.