Be More Chill, a show about a high-school nerd who takes a mysterious drug (an actual “chill pill”) that makes him popular, got one professional production at a Jersey Shore theater in 2015, dropped a cast album on the streaming platforms, and disappeared. Two years later, young fans started discovering the show online; before the year was out, it had been listened to 150 million times on Spotify. So the creators got an off-Broadway production together – and its initial run sold out in a day.