The over-the-top pop stars found their costume inspiration in marijuana leaves. VH1 reality TV star Evelyn Lozada posted this picture of Riri at a West Hollywood party (her ever-classy ex-boyfriend Chris Brown also attended dressed as a terrorist--that is a thing that happened) while Lady Gaga's makeup artist shared this snap of Gaga as "Princess High the Cannabis Queen." Mother Monster herself shared her costume on her website Little Monsters with the caption "Happy Highlaween!"
So whose inspiration took them higher? Which chart-topper smoked out the competition? Will they find themselves in a hot box of controversy?
Okay, we're done. Check out the two costumes in our gallery below.