The choreographed dance often performed after the formal waltz is commonly called the baile sorpresa.
The Spanish phrase means “surprise dance.” Unlike the traditional vals, which is usually elegant and formal, the baile sorpresa often uses popular music and deliberately unexpected choreography. The celebrant and her court may change steps, formations, music, or costumes to create a theatrical performance.
The routine is a relatively modern addition to many celebrations and is not a required element of a quinceañera. Its popularity reflects the influence of contemporary dance, music videos, social media, and family-produced entertainment.
Terminology can vary by country and family. Some people simply call the performance a surprise dance or a choreographed routine. It is important not to treat the baile sorpresa as the formal waltz itself: the two segments have different styles and customary purposes.