3. Ctenophores
These creatures look beautiful and freaky at the same time. They are among the oldest species on Earth. Ctenophores are truly gorgeous to look at, especially when they swim they create rainbows all around them. It’s not easy to collect them because they are super delicate and not much information was found until the beginning of blue-water scuba and submersible collecting.


Even though they appear so innocent and delicate, they are sinister and destructive of plankton organisms. They are from a few millimeters to 2 m long, and most of them are transparent and bioluminescent. They have no brain and no heart. Just like some of us, right?