Mariah sported a curve-hugging latex costume that showed off plenty of cleavage, which she paired with sequined red horns, wings, and a tiny pitchfork. She completed her devilish look with long diamond earrings and bangles and strappy black platforms.
The "We Belong Together" singer made the event a family affair, with her ex-husband, Nick Cannon, and their 5-year-old twins, Moroccan and Monroe, all getting into the Halloween spirit with her. Roe dressed up as Tangled's Rapunzel, while Roc went as Mario from Super Mario Bros.
Later in the evening, the America's Got Talent host swapped his costume for a gray shirt and matching beanie as he took on DJ duties, with little Moroccan, aka DJ Rocky, getting behind the deck with him.
Plenty of Mimi's famous friends also attended the party, including Tamar Braxton, Tamika Harris, Floyd Mayweather, Master P, and ET's Carly Steel, as well as her manager, Stella Bulochnikov.
Last year, Nick and the twins also helped Mariah celebrate the spooky holiday at a palatial Airbnb estate in Beverly Hills, California, as did the songstress' now-fiancé, James Packer. Mariah dressed up as a "glamorous witch," while Roe was the pink Power Ranger and Roc was Batman.
"They wanted to be super heroes," Mariah told ET. "They've been celebrating Halloween since August. So I figured, you know, we should have something fun and a haunted house and really be festive so they can enjoy the holidays."