Everyone knows what it feels like to be absolutely terrified. And while it might not be your favorite flavor of fun, you can't deny it's a rush. That's because your brain takes fear as a cue to start dishing out its own kind of halloween candy in the form of delicious neurotransmitters.

As explained by Bytesize Science—with the help of Abigail Marsh, Ph.D., associate professor of psychology at Georgetown University—there are actually a few different chemicals at play when your brain is gearing into "OH CRAP" mode. Of course there's trusty adrenaline, but cortisol and glucose play a big roll too, priming both your brain and your body to get the hell out of dodge in case that creak at the door is actually an axe murderer.

Of course, knowing how all this works doesn't let you stop it, and these ancient chemical wheels will still get set in motion the next time someone sneaks up behind you and yells in your ear. But at least it'll give you something to think about while you try to calm yourself down. [Bytesize Science]