https://www.odditycentral.com/pics/the-pacific-barreleye-fish-and-its-weird-see-through-head.html
The Pacific Barreleye Fish is a unique deep-sea creature that has a completely transparent head, which helps it sea in the dark. The fish gets its name from...
barreleye fishpacificweirdseehead
https://pubmed.ncbi.nlm.nih.gov/24648222/
We describe the bi-directed eyes of a mesopelagic teleost fish, Rhynchohyalus natalensis, that possesses an extensive lateral diverticulum to each tubular eye....
deep seareflectingopticsdiverticulareye