the fish with a transparent head

At first glance you may mistaken “Barreleyes” (Macropinna Microstoma) to inhabitant landscapes like Planet Degobah. This animal’s cranium is completely transparent, allowing it to view potential predators from extreme angles.

Such as directly through the top of its head.

The Barreleye has extremely light-sensitive eyes that can rotate within a transparent, fluid-filled shield [...]