There are many musical performances on cruise ships, but the Victrophonics on the Disney Fantasy (and its counterparts on other Disney cruise ships) is no side gig, but a major attraction on the company's ships.
Disney's iconic music, in period covers, almost every evening, in the main lobby on the ship, accompanied by a tap dancer and a vocalist, as well as performances by various Disney characters all around - this is a multifaceted event that attracts a large audience and is worth watching.