Halfway through the eight-minute Black History Month montage that is “Ring Bellz,” CyHi Da Prynce, aka “the rap Frederick Douglass,” straps up over tense horns and moves from posing as Martin to posing as Malcolm. SPOILER ALERT: toting an automatic, he peeks through the curtains and fires the bullet that killed King. The camera hovers on the balcony, and Cy-as-Martin falls down to die. He assassinated himself. It’s a heavy clip, well-produced and stocked with Civil Rights footage and CyHi’s growlingest flow to date.