Naturally occurring phenomena allowing for hallucinations or "visions"

So I am working on a concept for a location, wherein a sort of oracle will exist. This oracle will in no way be super natural rather the strange behavior of the oracle (a human for the sake of the question) will be the result of interaction with some naturally occurring chemical/compound.

• The placement is a naturally occurring cave system along the edge of a major mountain range
• Some sort of natural compound or chemical should exist in one specific portion of the cave network.
• The chemical/compound should cause hallucinations and if possible mild convulsions/shakes etc
• No effect should occur outside of the oracle's chamber/room/whatever
• Better if it can be triggered by simply being in a certain location rather than requiring drinking/eating
• The situation should not render the oracle completely unconscious but this can be waived for an otherwise good plan

What sort of naturally occurring phenomena could make this scenario happen? Answers should include both the compound and its effects as well as any setting specific requirements to make it possible.

posted over 7 years ago

James‭

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