I do remember visiting Kenidjack some years back, and the place was literally "buzzing" and vibrating around me! I hadn't ingested anything psychedelic that day, and could see no obvious natural explanation (although I don't rule this out at all). It wasn't "nasty" as such, although I was initially uneasy about the experience. I just had the feeling to treat the place with respect.
I stayed and had a lovely day.