This mysterious mushroom makes people see hundreds of tiny humans | ScienceDaily
(www.sciencedaily.com)
In the article they mention no specific substance has been isolated. Though, there are now 2 (or 3) varieties of mushroom each from a different location that provide similar hallucinations, so it might be easier to find the substance if it is shared by all the varieties and if there aren't a lot of other chemicals in common.
They do know it's not psilocybin or LSD (in these mushrooms).