unlike any living animal.” About the size of an adult human’s index finger, Mosura and its swimming flaps vaguely resemble a moth, which led researchers to call it the “sea moth.” ...

Paleontologists have discovered fossils of a 506 million-year-old tiny three-eyed predator nicknamed the “sea moth,” according to a new study.

The Mosura fentoni, or "sea moth," is a newly-discovered type of arthropod that would have lived in the deep sea more than 500 million years ago.