Marvel fans are still waiting on the X-Men to join the MCU in earnest, but the franchise recently teased the arrival of the mutant team with an alternate universe cameo of a former X-Men movie star. In the post-credits scene of The Marvels, Teyonah Parris' Monica Rambeau arrived in another universe and came face-to-face with a super-powered version of her mother, Maria, as well as the popular Hank McCoy, better known as Beast.