The new dance phenomenon is sweeping the world.

But it’s also coming at a time when people are grappling with the questions that haunt them: What is this all about?

What do we know about it?

And is it safe?ABC News is reporting on some of the latest research into the new wave of dance crazes.

In this video, Dr. Roberta Stoddard explains why this new wave is so dangerous, and what you need for the best dance.