The celebrities have begun trickling out of their castles, mansions, and forest lairs to host or hit up Halloween parties, collect their high-calorie holiday booty, and inspire jealousy-driven shut-ins like us to mock their outfits.

Here's Heidi Klum, dressed as a university-level Introduction to Physiology coursebook illustration. [Image via WENN]

Ice-T and Coco as the prison-industrial complex and capitalism; Bethenny Frankel as someone who only weighs three apples thanks to Skinnygirl; and Holly Madison as the European Central Bank. [Images via WENN]

These people dressed up as "family": Melissa Francis as Kourtney Kardashian, Jenna Wolfe as Khloe Kardashian, Lester Holt as Bruce Jenner Kardashian, Amy Roebuck as Kim Kardashian and Janice Huff as Kris Jenner Kardashian [Image via Getty]

Alan Cumming as early 20th-century Modesty [Image via Getty]

Kim Kardashian as Environmentalism; Camille Grammer as the Pirate's Booty guy's sister [Image via WENN]

Gwen Stefani as Princess Designated Driver [Image via Bauer-Griffin]

Nicky Hilton as Little Red Riding Socialite [Image via Bauer-Griffin]

David Arquette as a Man Who Makes us Feel Sorry for Him [Image via Pacific Coast News]

David Arquette again, dressed as Valor, and Chaz Bono sans costume); fashion designer Marc Bouwer as the 37th Village Person and actress Morgan Fairchild as Morgan Fairchild's Legacy [Images via Pacific Coast News, Getty]