"These obstacles make ibogaine "the Mount Everest of psychedelics," Olson says."
Another candidate would have been datura and related plants.
Obviously there was recklessness involved, but it certainly made an impression on me.
If they took datura your friends most likely experienced delusions (aka distorted perceptions or thinking - and you believe it is real).
It's a really reckless thing to mess around with under almost any circumstances.