A group of
Amanita Muscaria - otherwise known as Fly Agaric.

Maybe just about everyone's idea of a toadstool - red for danger and poisonous, with elves and goblins running around?

Yet this is not the whole truth, they are not poisonous
in the normal sense, but they are dangerous being very highly toxic! Reindeer love them, so it is reported that Laplanders use dried amanita to stupify them before they are rounded up!