These mushrooms will make a person sick soon after eating, can cause severe illness, and even lead to the death of both humans and pets alike. Colorado recently made a splash in the world when psychedelic mushrooms were legalized in Denver, but psilocybin mushrooms are not the only fancy fungi that can be found in the state. As the weather cools down and we all head outside for fall hikes, pumpkin patches, and autumn fun it is tempting to pick mushrooms we see growing in the wild. This is not advisable as many species that grow around the state are poisonous.