Xena: Warrior Princess did it. Buffy the Vampire Slayer did it. Scrubs did it. Even Psych did it. They all presented special musical episodes of their otherwise non-musical series – and tonight, thanks to a spell causing everyone to sing rather than speak, it happens on Once Upon a Time as well. And yes, that’s the same plot used for the “Once More with Feeling” musical episode of Buffy, the landmark episode with music and script by Joss Whedon.