jesse czebotar talks about demonic influence and demonic possesion. some "vessels" are only good for a short ride and some are good for a long time until a new host is needed.
casteneda talks about "inorganic beings" which is to say, beings that have energy and coherence but no biological (organic) body, also talked about sorcerers practicing to get to the state where they could retain their awareness after physical death.
somewhere in the midst of all that. we may talk about UFOs and aliens but the truth is perhaps closer to earth and more good vs evil than galactic triptych.