It's a Star-Studded Fright Night!

See Katy, Rihanna, Snoop and more scare up some fun in their Twitter pics


California Ghoul? While visiting Knott's Halloween Haunt, the annual event at Buena Park, Calif., amusement park Knott's Berry Farm, Perry got into the spooky spirit by getting her face painted like a skull. "Be honest with me, do I look tired?" she Tweeted.