re: do you believe in bigfoot, UFO's, or ghosts/demonic spirits?

Ghosts - Kind of. But hear me out:

In physics (which is the governing "rule book" for how the universe functions), the Law of Conservation of Energy states: "Energy cannot be created nor destroyed; rather, it transforms from one form to another."

Basically this leads me to believe that when you die, the energy that you possess must be transferred from your body to an outside location (since energy cannot be created or destroyed - only changed). Theoretically, this means to me that when your body ceases to function, the energy housed within your physical body (the energy that causes your brain to fire, reminds your heart to beat, involuntarily blinks your eyes or tells your lungs to breathe in oxygen) must be released somehow. This could, in theory, manifest itself in a "ghostly" form of your released energy as it floats around looking for an entity to transfer into.

nb4 "when you die, you go to heaven or hell"

ETA:
Bigfoot - As Mitch Hedberg so eloquently phrased it, "I think Bigfoot is blurry, that's the problem. It's not the photographer's fault. Bigfoot is blurry, and that's extra scary to me. There's a large, out-of-focus monster roaming the countryside. Run, he's fuzzy, get out of here."

UFOs - Probably...with Aliens too...How cocky of us to think out of the trillions of possible planets in the universe that we can't even see yet, we are the only intelligent life forms.