They're tiny, blobby, butt-shaped, and glow in the dark. What the heck are they? Scientists are still figuring them out.

But the latest research found tube worms and molluscs that thrive despite water pressure 250 times greater than at the surface and the total darkness.

Beneath the seafloor on the East Pacific Rise, an ocean ridge where several tectonic plates meet, giant white worms and other creatures are thriving in the cavities of hydrothermal vents.

Deep beneath the ice-encrusted Arctic seas near the North Pole, atop an inactive deep-sea volcano, a community of sea sponges has survived for centuries by eating the fossils of ancient extinct worms.