>>50474413That worked to Lovecraft's advantage. Calling the monster "indescribable" and leaving its appearance to your imagination makes it far scarier than anything anyone could actually write.
A Pokemon example would be Mimikyu. It's whole thing is that its true appearance is so horrifying that anyone who sees it dies. Because of this, we only ever see its eyes, because once you say that something is so horrifying that just looking at it kills people, there's no way it can live up to that.