Supernatural the book of monsters, demons, spirits and ghouls

Tulpas and Other Created Beings, part 1

They say that if enough people believe something, it's true. Well, politicians say that. Those of us who try to work with real things in the real world aren't as convinced, but we have to admit that it's possible to create something just by believing in it hard enough.
In the Tibetan mystical tradition, highly advanced lamas and naturally gifted laymen could give their thoughts and imaginings an actual physical existence. They're called tulpas, and they're tricky to handle.
A tulpa is, pure and simple, a being created by the act of someone imagining it. When the two of us were kids, we never had imaginary friends because the real world was just too damn weird, and we didn't want to make it any weirder. But-understatement alert-most kids aren't like we were, and every once in a while, the kind of process that creates an imaginary friend goes a little farther.
It's not just Tibetans who believe this, either. We found these two quotes side-by-side in Dad's journal and were never sure what they meant until we ran into the tulpa:
Determined will is the beginning of all magical operations... It is because men do not perfectly imagine and believe the result, that the arts (of magic) are uncertain, while they might be perfectly certain.
-Paracelsus

All things are possible to him that believeth.
-Mark 9:23

Later, Dad runs through some thoughts about tulpas. Thoughtforms are central to many magical practices. One in particular, eidolonic necromancy, is almost all about creating thoughtforms though magically intensified visualizations of certain spirits. Helena Blavatsky and other Theosophists-who were a bunch of wackos, by the way, but they stumbled across some truth because, as Bobby Singer said to us one day, even a blind pig gets an acorn once in a while-believed that they had created thoughtforms of all kinds of different astral beings. The Crowley school of occult practice is full of instances of created beings, too. About the tulpa specifically, Dad notes:
TULPA created through intense ritual visualizations known as DUBTHAB. Variation known as DRAGPOI form with the idea of harming another person. Physical form of TULPA becomes apparent to the senses after the mind can begin to sense its spirit presence. TULPA thus created, no matter the creator's intent, will gradually turn on the creator.