SPOTTED: Kelly Osbourne, Slash, Jason Priestley, Victoria Summer, Andy Garcia, Lucas Till and more Saturday night in Los Angeles, when MAC Cosmetics and makeup legend Rick Baker hosted a Monster Mash.

The evening celebrated MAC and Rick Baker’s limited edition makeup collection just in time for Halloween and guests came dressed up in full creative costumes.

Notable items from the evening include:

Kelly Osbourne, dressed as Dame Edna Everage, stayed in character throughout the evening. Her fiancé Matthew Mosshart dressed up as Blossom and the two enjoyed checking out a museum of Rick Baker’s incredible work on the second floor of the event.

Jason Priestley and wife Naomi dressed in Dia De Los Muertos-themed costumes and enjoyed a couple’s night out having a great time on the dance floor. Victoria Summer also hit the dance floor as the deejay played a mix of classic and current music including the ever-appropriate “Thriller.”

· Slash and wife Perla got into the Halloween spirit donning prosthetic horns. The two chatted and snapped photos with Rick Baker and stayed until nearly the end of the party.