There are actually several theories which are associated with this question. One of the first and foremost is that myths originated because they attempted to explain phenomenon which more primitive man couldn't understand, things like thunder or the ocean, by explaining with entities or system which they could identify with. Another theory states that myths were originally stories of the accolades of important champions or warriors. This theory is less accepted though because while it fits very well for certain mythologies, like the conquest of Ireland in the Book of Invasions, but ill fitting for things like the creation stories of the Native Americans. There are a myriad of other theories but those are the most prominent for myself.
There are many myths and tales of people doing witchcraft by putting ingredients in cauldrons and saying spells. Witches and wizards basically exist in mind and matter.
Monsters don't exsist! They cannot swallow you if they do not exsist.
Yes hobos do exsist. They are secret agents working for bill gates.
no!
we exist by god he created earth and people and everything else in ever existed or ever will exsist.
they don't exsist. this is why they don't exsist: http://www.youtube.com/watch?v=4MT5oNEHrNs
No.
Yes.
No.
Yes.
no
No, she was a myth.