The true threat of possession, channeling: None.

[Adonai One]

Alright, I haven't revealed it but I've been through hell and back messing in the metaphysical. I have concluded that possession, almost in all cases, occurs when you attract a lot of attention to yourself by being of a certain origin in your soul or by messing with certain occult knowledge.

I've experienced it and I am currently experiencing it. The symptoms go as far as your mouth being forced shut for a few moments, random blurbs coming out of your mouth and your body twitching sporadically. And this is with other entities trying to remove it. Depending on the entity, you'll forcibly speak statements that have a very alien syntax while using a demeanor of a 5 year old due to their immaturity in language and/or human experience.

If it gets worst than this, just start praying to the universe and somebody will help you.

I've experienced shocks of forcibly induced insanity, bad channeling full of deception (so easy to spot once it occurs frequently) and every possible worst-case scenario.

Conclusion: There is nothing to fear on this planet metaphysically if you are not out to cause damage to the planet. Even then, you'll get protection of sorts. This universe loves you very much. This planet is very well supported.