Stephen King is the master of horror -- but even he has never experienced anything quite as horrific as Donald Trump.

That's the gist of an open letter that's doing the rounds Tuesday, signed by King and more than 600 of his fellow well-known American writers. The luminaries include Cheryl Strayed, Dave Eggers, Junot Diaz, Amy Tan, Mary Roach, Tobias Wolff, Richard Russo, Michael Chabon and Roy Blount, Jr. 

"As writers, we are particularly aware of the many ways that language can be abused in the name of power," the letter reads. "American history, despite periods of nativism and bigotry, has from the first been a grand experiment in bringing people of different backgrounds together, not pitting them against one another."

"The rise of a political candidate who deliberately appeals to the basest and most violent elements in society, who encourages aggression among his followers, shouts down opponents, intimidates dissenters, and denigrates women and minorities, demands, from each of us, an immediate and forceful response."

The list of signatories includes more than 10 Pulitzer Prize winners -- but it's also astonishingly geographically diverse, with authors from the heartland more than holding their own against authors from the coasts. 

It's also growing fast, with more than 150 names being added to the list since it was first published online Tuesday morning. 

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A Twitter account called Writers On Trump has been set up by the letter's creators, novelists Andrew Altschul and Mark Slouka. There's also an online petition that anyone can sign; it currently boasts more than 3,000 signatures.

No word yet on whether King will make Trump the villain in his next novel; America may not be ready for something that terrifying. 

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