Or maybe it was originally conceived as a cure for headaches and the deers would naturally eat those mushrooms. But more than likely born out of somebody doing something initially that other people would class as stupid, turned out it worked better than intended and caught on from that.

Though I'd like your version too be true. Given we are well aware of drug and the influence of inspiration for many forms of art that have been zeniths in many areas of that. The influence upon science has not been as well looked into that I'm aware of. But odd articles: https://allthatsinteresting.com/amazing-drug-discoveries (though not sure that last one can be counted) with the discovery of DNA having some credit to recreational drugs.