Be sophisticated in this long black prom dress from Morgan and Co. With a plunging v-neck bodice, this junior-size prom gown has thin shoulder straps that criss cross the open back for an alluring look at prom, galas, and other formal events. The long skirt has a surprise beaded detail that tops the side slit, while this long black formal dress flows to the floor with a flourish. Surprisingly under $200, this long black prom dress is ready to turn heads without emptying your bank account.