Emma Roberts, Evan Peters & Halsey Were All at the "AHS" Halloween Party

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The stars from all 9 seasons of "American Horror Story" descended upon a famous cemetery for a frightfully fun Halloween bash.

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The hellraising went down Saturday night at FX's "American Horror Story" 100th Episode Celebration at Hollywood Forever Cemetery.

Longtime veterans Sarah Paulson and Emma Roberts attended and joked it up on the red carpet.

Paulson also posed for photos with co-stars Leslie Grossman and Billie Lourd, who are currently featured on "AHS: 1984."

Grossman and Lourd also appeared in the seasons "Cult" and "Apocalypse."

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Co-creator Ryan Murphy attended with fan-favorites Connie Britton and Dylan McDermott.

Britton and McDermott starred in Murphy's first season of the horror show, "Murder House."

McDermott has appeared in several seasons since, including "Asylum," "Apocalypse" and "1984."

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Angela Bassett was draped in leather at the Halloween party.

She's been responsible for some amazing characters on "AHS" through the years, and has starred in "Coven," "Hotel," "Freak Show," Roanoke," and "Apocalypse."

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Shortly after going Instagram official, Evan Peters and Halsey hit the red carpet for the first time as a couple.

Dressing up as Sonny Cher, the two were giving off vintage vibes.

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Kathy Bates went all in on her costume when she showed up as a werewolf.

Bates has been featured in many seasons of "AHS," and got especially medieval during "Roanoke" where she portrayed The Butcher.

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Newcomer Gus Kenworthy has been enjoying his time fighting serial killers in "1984."

He tapped into his inner dark side at the party by showing up as an impressive skeleton.

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"1984" star Zach Villa showed up as a polar opposite of his dark role as the Night Stalker, and added a flair of color to the spooky evening.