Anyone else catch him on Joe Rogan? He got real weird at one point and said he couldn't talk about a topic because it would put his life in danger
It certainly was a weird part of the otherwise fascinating podcast.
Turns out portobello mushrooms contain a decently large amount of agaritine, which can be made in to hydrazine, which can in turn be used for explosives or rocket fuel. Agaritine is also fairly cancerous/mutagenic to humans.
That's my best bet as to why he wouldn't talk about it, though the threat to his life I would think is more for comic effect.