Marine Hachetfish
With a face only an impenetrably dark sea cavern could love, marine hatchetfish can be found in mostly tropical seas worldwide, as well as in your nightmares. Like anglerfish and a number of other deep-sea swimming fish, hatchetfish use their bioluminescent inner organs to light their way. According to the Monterey Bay Aquarium, hatchetfish have the ability to adjust the focus of their eyes with startling accuracy, both close up or far away. They usually do not grow to be larger than 3 inches.
More information: https://www.montereybayaquarium.org/animal-guide/fishes/hatchetfish
