With the proper focus, it is of course possible to “create” a spirit. In some traditions, such a created thing is known as a thought-form or an elemental. I tend to refer to them as constructs. Another more technical occult term for a created spirit is “egregore”.
People can make constructs intentionally, or they can create them accidentally by focusing a lot of energy on a particular thought form, force, imagined entity, and so on.
I created an elemental once, I think thats what hes talking about...