Even Paris Hilton jumped on the Cyrus bandwagon, dressing up as the "Wrecking Ball" singer.
The hotel heiress wasn't the only celebrity in The Hills to dress up over the weekend. Neil Patrick Harris, Kelly Osbourne, Snooki and Fergie, among others, recently showed off their fancy Halloween garb. Have a look below at our list of 13 favorite celebrity costumes of 2013.
Hollywood is weird.