1. Heidi Klum as Jessica Rabbit from Who Framed Roger Rabbit.
2. Jessica Alba and Kelly Sawyer as Romy and Michele from Romy and Michele's High School Reunion.
3. Jesse Tyler Ferguson and Justin Mikita as Harry and Lloyd from Dumb and Dumber.
4. Beyoncé and Jay-Z as Barbie and Ken.
5. Nick Jonas as the Hamburglar.
6. Keke Palmer as Aaliyah.
7. Joe Jonas as Derek Zoolander from Zoolander.
8. Gigi Hadid as Sandy from Grease.
9. Iggy Azalea as Cruella de Vil from 101 Dalmatians.
10. Chrissy Teigen and John Legend as Princess Peach and Mario.
11. Neil Patrick Harris and his family as classic movie monsters.
Have a spooktacular night! Here's our family Halloween pic (via @projectphotoboo): Well done, @DavidBurtka!
12. Rihanna as Raphael from Teenage Mutant Ninja Turtles.
13. Kylie Jenner as Christina Aguilera.
14. Mindy Kaling as a beekeeper.
15. Camila Cabello as Princess Jasmine.
16. The Rock as the Hulk.
"Don't make angry. You wouldn't like me when I'm angry" ~ The People's Hulk #HappyHalloween
17. Katy Perry as *mic drop*.
18. Ashanti as Smurfette.
19. Ariana Grande and Mac Miller channeling The Matrix.
20. Khloe Kardashian as Storm from X-Men.
21. Joe Jonas as Chazz Michael Michaels from Blades of Glory.
22. Nicole Richie as Danny DeVito from Twins.
23. Kristen Bell and Dax Shepard as Daenerys and Khal Drogo from Game of Thrones.
I’m. The. Luckiest. “@daxshepard1: Khal Drogo & his Khaleesi, Darnerys Targaryen. His Moon & his Stars. ”
24. Lucy Hale as the Twitter bird.
25. Kevin Hart and Eniko Parrish decked out in '70s gear.
26. Halle Berry and her daughters as skeletons.
27. Channing Tatum and Jenna Dewan as the Cat in the Hat.
28. Chris Colfer as Grumpy Cat.
29. Emily Ratajkowski as Marge from The Simpsons.
30. Bette Midler as Winifred Sanderson, her character from Hocus Pocus.
31. Audrina Patridge as Madonna.
32. Janel Parrish as a cat.
33. Kathy Griffin as the deer Snapchat filter.
34. Martha Stewart as a dead nurse.
35. Ashley Benson as a doll.
36. Lauren Conrad as a mermaid.
37. And Ed Sheeran as Austin Powers.
CORRECTION
Eniko Parrish's name was misspelled in an earlier version of this post.
CORRECTION
Neil Patrick Harris and his family are dressed as classic movie monsters. A previous version of this post misidentified them as the Munsters.
UPDATE
An item in this post has been removed to adhere to BuzzFeed's editorial standards.