Eldritch horror is the horror of that which cannot simply be explained or all that is uncanny, unearthly or supernaturally strange, examples are Cthulhu, Biblically Accurate Angels, elves and general fae, or the sun (etcetera)! For more explanation are that which cannot be comprehended by humans, a well known author who's works fall under this would be H. P. Lovecraft: his work is a mixture of eldritch and cosmic horror (that which makes humanity futile, or like ants to be stepped on by something far bigger and generally better.). 👍