Lovecraft’s monsters threaten the physical and mental integrity of the human race. Their appearances are often delayed in the stories and their existences are announced by documents (newspaper clippings, photos, sound recordings etc.).
One never knows to what extent a given apparition is a monster, a god or the real presence of a being resurrected from its fossil state («At the mountains of madness»). It is difficult to rank the monsters hierarchically. Most of them are monsters of a single story and their reappearance in other stories are only a wink or quote. In the gallery of the painter Pickman, monsters come out of the picture frame.