Happy Halloween! Celebrities showed off their Halloween costumes on Twitter today after celebrating the "spooky" holiday.

Robert Pattinson and Kristen Stewart reportedly attended a Halloween party together and were spotted kissing and holding hands.

The couple who survived a cheating scandal with Stewart's former director Rupert Sanders, were spotted wearing transparent masks for the Halloween bash. Katy Perry was also at the party at Hollywood Forever Cementery, according to Us Weekly.

Perry was reportedly dressed as MTV's Jane the best friend of the star of "Daria."

Other celebrities attending Halloween parties in Hollywood included Chris Brown who dressed as a terrorist for a party on Greystone hosted by Rihanna, according to Us Weekly.

Miley Cyrus posted a photo of herself dressed as Nicki Minaj on her Twitter.

"@NICKIMINAJ you a stupppppidddd hoe" she tweeted along the picture.

Comedian Patton Oswalt pulled off an outstanding costume dressing as Spiderman's Doctor Octopus.

"Mission acomplished. With a LOT of help from (MYTHBUSTERS' Adam Savage)" he wrote on his Twitter.

Country singer LeAnn Rimes and her husband Eddie Cibrian dressed as Sandy and Danny from the popular musical "Grease," which many fans found ironic given the recent pass of Hurricane Sandy.