Happy Halloween! Check out the funniest, spookiest, and most creative costumes in Hollywood.
Mac Miller and Ariana Grande
Russell Wilson and Ciara
Max Greenfield, Hannah Simone, Jake Johnson, Zooey Deschanel, and Lamorne Morris
Neil Patrick Harris and David Burtka
Scott Disick and Kourtney Kardashian
Who says Halloween has to end on Oct. 31? The mom of three shared this Instagram pic with her whole family -- including her ex and their three kids, Mason, Penelope, and Reign -- dressed up as superheroes on Nov. 1, along with the adorable caption, "I know it's now November, but..."
Mariska Hargitay and Debra Messing
The Aerosmith frontman's holiday was downright cinematic! Tyler dressed up as Rhett Butler from Gone With the Wind when he attended Universal Studios Florida's Halloween Horror Nights, where he posed in the Vamp '55 scarezone, a homecoming parade complete with vampire greasers, football players and homecoming queens.
Sarah Michelle Gellar
Channing Tatum and Jenna Dewan Tatum
The Keeping Up With the Kardashians star and her three children -- Penelope, Reign and Mason -- dressed up as the Power Rangers. "Happy Halloween!! May the power be with you," Kourtney cleverly captioned her Halloween family photo.
Behati Prinsloo and Adam Levine
Blac Chyna and Rob Kardashian
Kelly Clarkson and Brandon Blackstock
Amber Rose and Val Chmerkovskiy
Khloe Kardashian and Tristan Thompson
Beyonce, Blue Ivy and Jay Z
The 19-year-old reality star channeled "Dirrty"-era Christina Aguilera for Halloween on Oct. 30, and nailed the costume, rocking the whole signature look from Xtina's 2002 video, including the striped bikini, bleached blonde-and-black hair, and even Aguilera's infamous cut-out leather chaps.