Watch out for signs of mold. If the thing is any environmentally friendly mold, white fuzzy mold, or dark black places (mildew) over the mushroom, do not eat it. Don’t fret if the thing is blue staining—This can be popular in Psilocybe mushrooms and an indicator which the mushrooms include https://magicchocolates.co.uk/product/wonder-bar-chocolate-mushroom/