>>516He probably means a former of "tulpa" which is basically a separate consciousness that exists in your own mind, with its own free will and personality. A lot of the crystal healing/spirit traveller's types claim to create tulpa for themselves, and apparently they don't go away once they are formed, and live alongside you like an invisible being only you can communicate with. Imagine Ryuk from Death Note, or even Slenderman.
I've never heard of people creating places in their minds that they can visit and travel to, but I guess that sort of goes along with tranches and spirit traveling stuff, huh?