Most prom dresses live in relative obscurity. Oh, sure, they have that one night of glory, swishing and showing off on the dance floor. But then back to the closet they go. The exception is dress No.

Jenna Love, 15, emerged from a dressing room with a nervous smile that grew into a grin as girls started to gather around her and fuss with the bright pink gown she was wearing. It might need to be ...