On a rainy October day 5 years ago, I messed up my mushroom roast. We had spent a long day hiking in thick north-east Estonian forests near Lake Peipus, gathering different Boletus s pecies from this chilly and foggy mushroom heaven. Later, back home, after spending hours cleaning and preparing mushrooms, the smell of freshly roasted mushrooms floated in the air and my mind was prepared for the dinner. The first morsel, however, brought me painfully back to reality as the roast had a distinctively bitter taste that overshadowed all other flavours and spices. In the forest we had probably mistakenly picked a bitter bolete Tylopilus felleus among young porcini Boletus edulis. One of such specimens is usually enough to make you throw away your dish. I was not a victim of, well, mimicry, but of my limited ability to distinguish similar species that had different properties or applicability. The same dilemma is faced by many species who act as receivers in mimicry, as they too need to distinguish between organisms that are edible or inedible, harmless or dangerous, species-mates or predators and so on. Even the bitter taste of Tylopilus felleus is supposedly part of chemical defence system that mushrooms have against some fungivorous insects (Hackman and Meinander 1979: 53; Spiteller 2015).