Fly agaric, the go-to toadstool of fairy tale illustrations. This one must have emerged the previous night: the red of the cap is still bright, not washed out after rain. The white ‘warts’, remnants of a veil which protected the cap as it was forcing its way through the soil, are still intact. And the cap has not yet started to spread and flatten.
or the best chances of finding some, look where there’s birch trees around.