It's a scary time of year to be in Hollywood!

Tons of celebs stepped out for Universal Studios Hollywood's Halloween Horror Nights over the weekend. Demi Lovato brought a bunch of pals with her, including BFF Hanna Beth, as did Dancing with the Star castmates David Arquette, Ricki Lake, Kym Johnson, Chaz Bono and Cheryl Burke.

Demi had such a great time at the amusement park that she even Tweeted about it, writing, "Just thinking about how excited I am for Halloween! Went to @HorrorNights @UniStudios this weekend and it was sooooo scary - loved it!!"

Wilmer Valderama, Elijah Wood and former One Tree Hill star Chad Michael Murray also hung out with some ghastly creatures.

But David with his old co-star, Scream's Ghostface Killer? Hands down the funniest duo of the day. Sorry, Ricki!

The event runs at Universal Studios through October 31.