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Maroon 5 threw their 8th annual Halloween bash at a Hollywood cemetery Wednesday night, attracting everyone from RPatts and KStew to Katy Perry and Chris Evans.

Katy and her BFF Shannon Woodward channeled MTV's '90s cartoon Daria (Katy tweeted the above pic before the party), while Rob and Kristen donned their usual garb -- jeans and t-shirts -- but threw on Halloween masks to get in the spirit, as documented in photographs taken at the party.

Pics: Crazy Celebrity Halloween Costumes

In celeb costume highlights according to a partygoer, recent Emmy winner Aaron Paul dressed as Max from Where the Wild Things Are, while comedians Craig Robinson and Aziz Ansari went as a superhero and a Thomas the Tank engine-esque train, respectively. Abbie Cornish donned a Morticia Addams-esque black dress and black wig with dramatic pale makeup and red lips to match, while Rose McGowan dressed as an ice queen, and Maroon 5 bass player Mickey Madden bore an uncanny resemblance in his costume of dubstep DJ and producer Skrillex. Ricky Gervais pal Stephen Merchant dressed as a king, while former United States of Tara star Brie Larson wore a Lucille Ball-esque get-up. Others at the party included Captain America star Chris Evans, Radiohead frontman Thom Yorke, comedian Jamie Kennedy, and of course, the other members of Maroon 5.

The down-to-earth, festive atmosphere left no room for egos, with stars sidling up to the bar to order their own drinks, and even in one instance politely indulging the bartender's request for a photo.

Related: Pumpkin Patch Kids

The creepy bash recalled Maroon 5 frontman Adam Levine's recent stint on American Horror Story, taking place half inside a mausoleum, and half outdoors at Hollywood Forever Cemetery -- the final resting place of stars including Rudolph Valentino, Douglas Fairbacks and Dee Dee and Johnny Ramone. The carnival-themed party was sponsored by Patron tequila, and featured several tequila stations, an In-N-Out burger truck, a hot dog truck, a Coffee Bean and Tea Leaf coffee bar, popcorn and cotton candy stands, a Patron photo set-up, and carnival games including skee ball and a Patron ring toss. (The prize was sadly not a bottle of Patron, but a stuffed animal.)

PICS: More Photos From the Halloween Party, Including Rob Pattinson and Kristen Stewart