These appeared on our back lawn (grass) overnight.

I wonder what the consequences would be be if I harvested and eat them: would I be nourished by a gourmet experience, halucinating, or in the hands of an undertaker?

As I understand it, pharmacists in France are required to have the information to hand to answer these questions.

So, small as the chance must be, have I a pharmacist follower (from France or elsewhere) who can give me a steer?