We are land creatures: We breathe air, walk only on solid ground, and rarely move up and down unless we're at an elevator. We're used to this world, and we know the shapes of animals we might run into on land (although we still get surprised sometimes).

But even now, at this modern age, the titanic ocean that surrounds us still hides many fantastic secrets within it that astound us. Most of these surprises are biological in nature, turning out the most incredible, alien-looking and bizarre life forms, so different from our own, yet fascinating to see.

1. Barreleye Fish



With its transparent head with its big, tennis ball eyes looking out of it, this fish is one of the most extraordinary creatures I've ever seen.

3. Salp



The salp plays an important role in the ocean, as it turns its own bodily waste into carbon packages that sink to the bottom of the ocean and effciently removes carbon from the water's surface.

5. Sea Spiders



If you thought the ocean is the one place where you won't run into spiders, think again! However, although they look a lot like our land spiders, there is no genetic correlation between them and they are completely different creatures.