What the hell are they?????????
These are the Adaptareans!
FYI, these creatures are symmetric, so the view I give you is essentially mirrored on the other side of the creature.
The creature began as a simple, mainly sessile creature (able to move when resources are depleted), with four limbs, two eyes, one central gill-fin, and two sensory-fins which doubled as osmosis ingestion limbs. This row depicts several of the variations developed, moving from the original form to a very sea-star-esque form. As you can see, the gills changed from external gills to gill slits, going through some limb-forms to get there. The sensory-mouth fins turned into limbs, which eventually fused into a single ring.
The last two species of the top row were the first to attempt switching to a right-side-up lifestyle, and that last species was the first to be successful and adopt it fully. On this species, the gills are fully fused with the sensory ring-limb. This species was very successful, thanks to its right-side-up movement ability, combined with the traditional hanging. This species eventually began to live closer and closer to water, even venturing into the seas!
This row begins with the last species of the first row, for comparison. This species had several strange offshoots, including the blue one pictured: this one developed a bizarre "second loop" of gill-ring.
The next species was the first that adapted to an underwater lifestyle; its legs were able, underwater, to push against the ground and carry it about. This species also were the first to develop bioluminescence, which shone from the line of five nodes along its ring. These were used for communication as well as making one visible to its fellows. Finally, they also developed a voluntary respiratory cycle. With a well-timed exhalation, they could fill their gill area with gas, and thus float, propelling themselves upward.
Now comes the switch to a fully aquatic lifestyle, as the creature branched some octopus-like brethren. The first two pictured are the most octopus-like that existed. This also marks the switch from a radial symmetry to a bilateral symmetry, with front and back defined. The "back" eye migrated up to sit on the backside of the sac. The sensory-ring on these changed into a veritable lung-sensory sac. This huge area could be filled with gas by exhalation, and these creatures developed the ability to a higher degree of skill. The ingestion by osmosis was usurped by an eating mouth, located in the back underside of the sac, and an anus, located directly beneath the mouth. The line of luminescent nodes changed into a simple pair, located on either side of the sac. There was also a development of a crude cartilage in the front tip of the body, for protection and cushioning when running into various undersea objects.
Below these we see the next branch specie, which lost the ability to float in favor of the ability to propel forcefully. This gas exhalation was through the mouth at the back of the sac, while inhalation continued to be through the gill slits. The anus migrated further away from the mouth, toward the center of the tentacles. This species was highly streamlined for speed.
Below that specie is a very similar specie, parent and offspring, only depicted to show an example of the variety.
Next in line, developed from the streamlined speeders, is the beginning of a crustacean-like development. The wart-bumps become actual arms, for sensing and manipulating the environment. The cartilage has expanded, protecting now the full front half of the creature. If you can see the "corner" on the underside, almost like the edge of a ribcage, that is where the cartilage ends.
I'm getting tired of writing now, but I must press on! Next we have basically a more advanced version of the previous species. The arms have become harder, shell-like in texture. The biggest visible change is that The back two arms have developed claws. These are for gripping food and placing it inside the mouth, which is now hidden underneath the sac. I've drawn in the propulsion gas.
Above that are two later evolutions which developed clinging and walking. These species threw out the bioluminescent node. In them the "back" eye migrated down to the top of the tentacles, and they switched directions - What previous species treated as their "front", these treat as their behind, so, in comparison to the others you could say these walk backwards (not to mention upside down!) They make extensive use of the sac-inflation method to float to the underwater ceilings, where they spend most of their time. In a strange twist of events, this line of evolution has brought its subjects down off the ceiling only to eventually bring them back up to it!