Hulu's Only Murders in the Building has quickly become one of the biggest shows of 2021, and it's about to become one of the biggest Halloween costumes of the year. With a star-studded cast featuring Selena Gomez, Martin Short, and Steve Martin, the show has plenty of characters to draw inspiration from. You can channel the true-crime trio for a fun group costume with friends, or you can do a solo costume as you dress up as Gomez's Mabel Mora. Honestly, we'll take any excuse to buy the character's incredibly fashionable wardrobe. See more Halloween costume ideas for the show ahead.