An alien race (actually a very alien in the adjective sense Fantasy Race, but it could work as either) I have come up with are the Kshya (which is an onomotopoeia for the noise they make when unsealing their mouth, the only noise they make).
They are hexapoidal invertebrates (with a faux skeleton constructed of hydromuscles like a spider in rings and columns, plus cartilage), with six eyes between each leg, which ends in a flexible tentacle with small suckers on it, allowing them to walk on flat surfaces that aren't too slick. Lifting the leg in the direction they face means that they have binocular vision. They usually have between 1 and 3 legs lifted for tool use if they have to carry something, since standing on two is hard. Their body is flat and coin shaped and dully coloured green, red, or yellowish, sometimes mottled between shades, and the bottom of the coin bulges outward in a rounded pattern- from the bottom it is radiating lines with one circule bisecting the lines. Thus from any given angle, the bottom half of a Kshya looks like a manic grin, while the top has cute little glassy eyes. Kshya can walk completely inverted due to the flexibility of their tentacles, but they usually do not as the grin gives them a preferred direction. And cause all their pouches full of stuff would jangle around and stuff might fall out.
Something like
with a flatter top, plus the legs between each of the six eyes. A Kshya with 1 leg lifted will usually rest it on her head's flat surface, meaning while radially symmetrical they somtimes act like they have a biased direction out of laziness if said arm is carrying something heavy- 'backpacks' will be affixed to the flat top with an arm as support but never via strapping to the grin for a very good reason outlined below (for one, it's hollow and would collapse)
The overall effect of the grin is, in my opinion, cute. At least until they open their mouth. The Kshya mouth opens by the 'grin' unhinging. It can unhinge to any degree save falling off, from any angle. The inside of the mouth has six tiny black eyes spaced around the edge and a huge, horrific looking mouth full of teeth (although in regular patterns there are non-pointed teeth for plant eating, it is still scary looking). Why the eyes? The 'grin' is actually the body of a tiny male (the picture is rather rough in showing the size disparity, it is about 2:1) attached to the female. At maturity, the thin and wide males (whose organs are arranged differently from a female's to produce this, and have a much more flexible torso) will flex up and attach, the tiny stubby legs locking in with the female's gripping ridges there and basically atrophying over years. He lives for quite a long time, almost as long as a female if cared for properly, but if he falls off after a brief period of disappointment and reproducing any last spawn of his, the female will go obtain a new one.
The male chews up food for the female as a curtosy, as he has a bigger mouth. When she is hungry, he arches upwards (the grin appears to dent inwards), and they 'kiss'. Then the male vomits in her mouth. Charmingly romantic. Surplus food can be carried in the male, as he is convex. Damage to his eyes might occur but he is nearly blind and doesn't use them much being facing inwards most of the time. Despite this, he is rather well cared for like a pet and Kshya try to avoid eye damage (it is why the eyes were evolutionarily and artificially selected to be on the edge). Small, less functional eyes and larger mouth is considered a desirable ('cute', perhaps) trait, but Kshya reject eyeless males or males with eyes on the outside as freakish so the logical extreme of this breeding program or the more sensible configuration, respectively, have never occured. It appears to be aesthetic, but born of evolutionary concerns about males not being able to walk around (nowadays someone can just carry them to whereever in a box, but it's still psychologically present). The inward dent was originally a protective adaptation for the smaller, weaker male as he was carted around being mated with for life, so it makes sense that eyes on the outside is unnerving (and imagine a human with eyes on the back of their head- freaky).
I would write a huge paragraph on how a caste-based pheromonal control ecology has affected their psychology (including the human attempts to understand that they are not 'under control' or 'coerced' to follow pheromonal orders and that despite being under the complete, even suicidial direction of a higher caste will still retain individuality including fashion taste and friendships with other kshya, or that they have (unlike stupid hive mind species in most fiction) learned to respect human life mostly because people have demonstrated a bizarre tendency to attack with disproportionate force for loss of underlings) and how other aspects of their biology affect their psychology (such as their bodyshape meaning that backpacks on the top and lots of leg pouches are the preferred clothing- pouches on pouches that would make Liefield proud). But nobody really cares so I'll spare you.
Still, I think it's cool. I haven't a clue how they'd develop sentience, but I think the 'how did these things get sentient' problem is a bottleneck for too many cool ideas as long as they aren't completely nonsensical. Sentient solitary preditors? Sure! The Ur-Quan made it work, especially with their "We clawed our way up to civilisation despite our rage, Human. We mastered ourself." arrogance about their civilisation. So why not Sentient hivemind?
or Sentient 'semihivemind' as these are. I've never like hiveminds in fiction. Ants should
like being ants. They shouldn't feel like they have no individual will, or if they do they shouldn't mind being instruments. Obeying proper pheromone-registered commands should be as natural as walking or talking to them, and if they're sentient enough to talk to they should have an alien perspective on these things.
[edit: the idea was inspired by the anglerfish who attach to a female and eventually atrophy into a tiny attached penis and organs humping the larger female]