Mysterious Creatures
Other than that, these creatures are very mysterious. Very little is known about them other than the few stated facts. It's difficult to study a Blue Dragon due to the rarity that they are... Even coming across one likely won't happen in your lifetime!
They Contribute to the Ecosystem
You might think that these little slugs are probably just interesting to look at, but that's not the case! In fact, if it weren't for them, there would be an overpopulation of the extremely deadly man-of-war jellyfish. They would overwhelm the small fish that they prey on, which would easily cause a huge rift in the ocean's food chain. Plus, more of them would end up on beaches, which would be bad for humans.