It's not Nathan Fillion, nor is it Summer Glau or Morena Baccarin. No, it's the kid who played young Simon Tam for mere minutes in one episode: Zac Efron.

There's the heartthrob as a pre-teen, playing the pre-teen Simon Tam in the first few minutes of the Firefly episode "Safe." And here you thought the High School Musical star was a brand of chocolate you wanted nowhere near your geek peanut butter....