...commonly known as the fly agaric or fly amanita.
This is the mushroom that everyone knows - the 'fairy toadstool'. It's poisonous but people still eat it for its hallucogenic properties - it's a 'magic mushroom'!
It would make a much better photograph if they grew in threes - and preferably in three different sizes - but, unfortunately, they tend to be solitary... they do in my part of the world anyway!