'Hotel Transylvania' Stars Selena Gomez, Andy Samberg School Us In Vampires 101

One of the lesser-known side effects of being in a vampire movie, any vampire movie, is as follows: Immediately after being cast, you are hastily inducted into a secret society of experts on the blood-sucking befanged, where you receive professional instruction, informational packets and several documentary DVDs on the general history and biology of vampires. (You also get a nifty key chain! Or so we've heard.)

So, with Selena Gomez and Andy Samberg's "Hotel Transylvania" out this week, MTV News' Josh Horowitz took advantage of their newly gained knowledge to get some inside scoop on what, exactly, the deal is with vampires.

Among the surprising answers: The desire to drain human beings of their life's essence is a simple matter of biology, not a character flaw (take that, anti-vampire bigots!). Also, Justin Bieber is, shockingly, not a vampire. (Or at least his ladyfriend won't say so in public.) But hey, if you want a firsthand account of what it's like to guzzle human blood, Selena has all the info you'll ever need:

"It was salty," she said. Which sounded exceptionally hardcore, until a moment later when she admitted: "It was my own."

Euuuuugh. Okay, then! Just, y'know, don't do that whole self-exsanguinating thing too often; we hear it'll make you go blind.

Do Selena and Andy seem like vampire experts to you? Tell us in the comments and on Twitter!