Cardi B, a 33-year-old rapper, wore a strapless mermaid dress for her after-party at The Grand nightclub in Boston on Thursday. The design was inspired by London-based label Di Petsa and was printed with a seashell bra and gray-and-black scales. The event was part of her ongoing promotional activities, including launching her hair care brand, Grow-Good Beauty, and a 35-date arena tour.