I believe this is were we hit the culture clash, MaCan. This would not be something done in the Western world, and if it was, it would be considered part of the dark arts.
I don't think my uncle was into anything that would summons an evil entity but can't be certain about his friend,I'm leaning towards something in the area they were camping as my first thought but nothing is out of the question.You have some interesting customs.
Yes of course ma'am, I do understand what you mean about cultural clash
By my story, of course I didn't mean to say Mr.Oz's uncle and his friend might have done something similar. I was just comparing the behavior and the strength of the summoned entity in my story with the behavior and strength Mr.Oz told in his story of his uncle's friend. But maybe I was a bit too carried away with my own story so it rather blurred the point that people would easily mistaken it, my apologized.
As we can see, there're indeed undeniable similarities in what I've witnessed myself with that implied in Mr.Oz's story, concerning behaviors (give or take it, between tiger and wolf) and (perhaps) the level of strength displayed by two different persons.
And, for both cases, we also have two persons who didn't remember at all what had happened to them on a certain span of time; the time when they were possessed-of course, by assuming if what happened to Mr.Oz's uncle's friend was also a possession case.
I'd also like to say that, this kind of possession however, does not always have to be triggered by a person who summons a spiritual entity in the first place as it can also happen without a person literally and/or deliberately summons anything.
As for the trigger for the possession cases without the involvement of a summoner itself, it can be many things. I'm afraid I won't be able to point out a single exact reason that might've been the trigger for Mr.Oz's uncle's friend's possession case.
In Indonesia, we have something like a set of rules of proper conduct/ettiquete, that must be strictly followed to the letter in some certain public spaces, especially at camping sites nearby to or in the area of jungle, hill or mountain. These rules are even written on a board and placed almost everywhere in such sites.
Those included in these rules are commonly as follows; if you have to urinate or something like that, you can't do it especially on certain spots like under that tree or behind this bushes, etc. During the night time, don't yell. During the night time, don't talk too loud. During the night time, no guitar/singing (sounds silly, I know). Don't swear on this camp site. Sexual activities are forbidden. Alcohol is not allowed here. Etc.
That'd be up to the things that sounded even more silly, like; do not sleep on certain spots, do not whistle, do not say a certain word, do not act or speak like you're a brave person and that you're not afraid of supernatural entities (acting 'sompral' in Sundanese, or 'arrogant' in English), do not try to challenge supernatural entities to show themselves up or to fight, etc.
Maybe you're now asking as to how come there're so many silly rules to follow in a camping site alone?
Because 'they' are exist everywhere, including in these places. Imagine what kind of supernatural entity that lurks behind the veil in such areas so far away from people? Maybe you don't even want to know, as most likely, they don't like human, and by judging from a fact that they chose to stay at remote places, it won't be far from truth.
Thus, the rules of maintaining ettiquete are there in these camp sites far away from people, mainly for a sole reason; security for the campers, as the result of (normally) an agreement between the owner of these camping sites with the 'original inhabitants' of the area, so to say.
No camp sites will be established in a remote jungle/watery area unless there's such an agreement made beforehand around here, because it'd be the only way available to ensure campers' safety for as long as they stay in those areas (for a price of course, and for the campers' themselves, the price would be to follow the rules), and 'they' on the other side would agree to tolerate the presence of people in their teritorry to some extent.
And here's where everything gets interesting; broke the rules there, and most likely you'll get yourself possessed-it's somekind of common warning for light transgressions upon the agreement, around here and in this case, btw. And near the jungle area, the behavior shown by the possessed persons would usually indicate those of animals' like monkey, snake, or tiger (I didn't mention wolf btw, since unlike in many European countries and US, we don't seem to have wolves in Indonesia except for those in the zoos).
Also, this type of possession case happened around here-like a lot.
For more serious cases, 'they' are often took the persons they possessed away from the camp sites and just 'dumped' them somewhere deep in the jungle. It happened quite a lot in a particular mountain national nature preservation and camping park area of Gunung Gede, West Java, that campers just 'got lost' deep in the mountain jungle for days without remembering what happened, before the rescue team finally managed to find them-if they're lucky, that is.
Thus, it led me to believe that one possibility that took place in Mr.Oz's story is that of this type of possession, and I also agree it had something to do with the camping site itself. But also in the case of Mr.Oz's uncle's friend, I'd say the friend was lucky that the spirit seemed to still have a good will of returning him to the camping site.