You are looking at the official start of the Golden Age of Science Fiction. This July 1939 cover of Astounding Science-Fiction features Coeurl. He is a massive, black, cat-like predator stalking a newly arrived human spaceship.

James Francis Graves Gladney painted this to illustrate A. E. van Vogt's Black Destroyer. The story says Coeurl has tentacles. Gladney left them off. It is a solid editorial choice.

Edited by John W. Campbell Jr., this specific issue also held Isaac Asimov's first sold story. Claim a monumental piece of speculative fiction history.