Hi I'm spitting out biology (and a liiiiitle bit cultural) musings more of them. These guys are actually terrestrial holothurians (sea cucumbers). I'm putting my stonks into echinodermata we have to believe in their Powers to evolve new and exciting shapes.
The people who keep symbiotic fish in their tentacles call themselves Anemones, while the ones that reject the fish as parasites and wear shell-like hats over most of their tentacles call themselves Nautilus. In the modern day there is an increasing population of those who consider themselves neither of these things but due to the history of these two cultures there isn't a widely accepted colloquial name for the species as a whole.
They're not cnidarians so they don't possess stinging cells, but they produce a thick venomous mucous from their tentacles that causes paralysis and inflammation on contact for various other animals. They evolved as social ambush predators that would jump on their prey and slather this mucous over them to subdue them. Their ideal diet is like 60% meat and 30% fruits, with bonus whatever the fuck else they feel like eating as a treat.
The venomous mucous may have been what initially started the Nautiluses' practice of covering most of their tentacles, along with protection from the sun and aerial predators. They have a long history as a multi-species people, and keeping contact venom just exposed around your loved ones without resistance to it is just plain dangerous. These days it's more of a visual identification and religious thing though.
These guys don't have real eyes, but are covered in light sensing cells all across their skin. They have shit visual acuity and can't see very far, but they're usually aware of the general silhouette of large objects a few feet around them, and are sensitive to movement. The Anemones, at least, formed a symbiotic relationship with a species of amphibious fish partially due to them being able to see farther and with higher acuity and warn them of things they might not have picked up on by themselves.
There's a lot of in-universe debate over the exact intelligence of the clownfish, but the average seems to be kind of parrot-like, with occasional exceptionally intelligent, probably sapient individuals. They're hard to study, because they're usually extremely shy towards other people, plus Anemones tend to develop a very strong bond with their clowns that skews their perception of what their own fish is capable of. In the modern day the relationship between Anemones and their fish is largely religious rather than out of any real practical necessity; the Anemone religious hegemony considers these fish as one half of a full person, and places an extreme importance on maintaining this relationship. This is usually fine and what ever, but can place Anemones and clownfish alike into difficult situations when the relationship is unwanted or cannot be maintained properly for whatever reason. It's also the reason Anemones and Nautilus have historically considered themselves separate, often rival species; the presence of the clowns or lackthereof have been considered mutually repulsive and a sign of something being deeply Wrong about the other group.
Most terrestrial holothurians are small, trundling insectivores, but there is one large species these guys share a close evolutionary relationship with. The dropbear are solitary, arboreal ambush predators that used to share much of their range with Anemones, but are currently critically endangered in the wild. Anemones, with their very low visual acuity and poor sense of smell, have a very hard time distinguishing dropbears from members of their own species. It's thought the need to tell friend apart from foe is what drove them to develop complex vocal capabilities.
Side note the Example Anemone here is wearing an extremely hastily designed example of traditional Anemone accessories; they didn't have a nudity taboo and actually prefer to keep most of their skin uncovered so they can see, but they enjoyed wearing accessories with tactile or audible elements built into it. Beads were often placed so they'd click together when moving, and combined with knots in the cords were often arranged according to their traditional system of cord "writing" so that people could read each other's clothing.
These guys support themselves on land through an endoskeleton made up of a network of mesodermal ossicles and catch connective tissue. When threatened, they can dramatically loosen their skin and let a predator or perhaps a guy easily tear off whatever part of their body they've grabbed, allowing for an easy getaway with relatively easy wounds to regenerate. This easily gooped skeletal structure does make them very prone to fatigue though. It was fine, because they're ambush predators. They were just supposed to be sitting there most of the day. Please.
