3 mind-blowing facts about them:

They eat their own brains: As larvae, they swim around with a basic nervous system. Once they find a rock to settle on permanently, they no longer need to think so they digest and absorb their own brain to recycle the energy.

They are closer to us than to crabs: Despite looking like jelly blobs, they possess a primitive backbone (notochord) in their youth. This makes them evolutionarily closer to humans and fish than to clams, crabs, or octopuses.

Wolverine-level regeneration: If a predator bites off their "panda face," they can completely regrow any missing organ. A whole new individual can regenerate from just a tiny fragment of leftover tissue.