Thanks for the link. Just finished watching it for the third time. I'm trying to figure out if it's Japan's version of "Invasion of the Body Snatchers". The director had survived WWII as a soldier and POW and became something of a pacifist after the war. The movie pokes fun at the bourgeoisie while begging the cast not to eat the mushrooms.
In any case, if that singer had asked me to eat the mushrooms, I very well might have said 'Yes'!