Mellanoids were very uncommon in Starfleet following first contact in 2360 and joining the Federation during the Dominion War in 2373. Most mellanoids in space careers joined the United Mellanus Space Program. (see also: Mellanoid Space Exploration) Felime Trox was an NCO during the Dominion War. Eaurp Guz was the first to be an officer in 2379, and there's only a small handful of other mellanoids in Starfleet. As of the 2380s a few more are trickling in each year.

In the late 2390s and the 2400s, Mellanus Space Program gets essentially integrated into starfleet, and Mellanoids start absolutely pouring into starfleet.

Logo of the United Mellanoid Space Program.

fig 1: Just a small window into the possible variation of Mellanoid body plans. Humanoid and humanoid variations are the most common, but practically anything is possible. fig 2: Ditto for faces. fig 3: Cutaway of a mellanoid's face showing the spongy inside of the gelatin skull, the mouth, and an eyeball. fig 4: skeletal gelatin inside a mellanoid hand resembles a mushier, less consistent version of humanoid hand anatomy. fig 5 (left, oops): The visceral and skeletal goo support each other, without the visceral goo acting as muscle the skeletal goo flops. fig 5 (right): a three-lunged individual, with a close up showing the foamy structure of their lungs. fig 6: Demonstration that all forms of slime are interchangeable. fig 7: Mellanoids generally lack genitalia (unless they want them!) fig 8A: three infants (slime worms). fig 8B: the same individuals as children. fig 8C: the same individuals as young adults.

Mellanoids have differing consistency depending upon emotional state. They may get softer when sad or tired, or bouncy when startled. They may become drippy when anxious. Even intense positive emotion can lead to melting sometimes. The default texture is like a somewhat tough jello, jiggly but not sticky and with no residue left behind. When very sad they are capable of crying, with the sclera of their eyes melting alongside other parts of their face and body. In addition to losing cohesion with strong emotional state or sleepiness, Mellanoids can voluntarily liquify and move as a liquid, and even accomplish a limited degree of shapeshifting in this amorphous state. When sleeping or otherwise unconscious, mellanoids will melt into their amorphous form, and either spread thin so they can absorb air through their body, or if they're sleeping in a padded tub, they will manifest lung-foam on the top surface to continue to take in air into their body.

N.B.: Mellanoid consistency and physics is also just kinda whatever works! They're cartoon characters from an animated cartoon and fanart for another animated cartoon. If it feels right, it probably is right, even if it contradicts something I've said in the previous paragraph. The whole point of slimegirl emotional consistency to me is that it is a visual symbolism for how strong emotions can feel--if you feel like you're falling apart then that's what you will look like, if your heart melts you're literally melting, if you feel tense and rigid then you'll be tough and rubbery. And doubtless different mellanoids can be more capable or less capable of not just emotional regulation, but hiding the visible extent of these emotions.

Here is a reference sheet showing variation in existing Mellanoid Slime characters, and also a warp ship and a steam engine for reasons which are unlikely to become clear again soon. NB: following image contains drawings by myself, Ray Daly, and James, as well as a few screenshots of Star Trek Prodigy. Names which are not native mellanoid names are put in quotes.

The bioluminescence here is exaggerated so you can see it--it would really be much much more subtle, to the point that it might be difficult to even see it as colored light.

Happy Transgender Day of Visibility from planet Mellanus!

From Right to Left:

Ensign Eaurp Guz (she/her), engineer, USS Cerritos.

Captain Slamtha Uzgoel (she/her), skipper of the Orion Syndicate ship S.S. Good Afternoon.

Lieutenant Be'Iw, Daughter of Kozin (she/ghaH), officer, Klingon Defense Force.

Ensign Utut Arobi (she/any), science officer, USS Diagne.

Ms. Oihre (she/her), former cultist.

Ensign T'oumii Ela'as (he/any), science officer, USS Feynman.

Crewman Visca Limax (she/her), former United Mellanus Space Program astronaut; enlisted engineer, USS Hypatia.

Mr. Twizzle Bajeeziz (he/they/it), amateur subspace astronomer and carpenter.

Cadet Murf (he/him), oddly skilled toddler, USS Protostar.

lmaooo. Eaurp Guz is a Mellanoid Slime Worm, but the only mellanoid slime worm in canon is Murf from Star Trek: Prodigy, and he's an infant/toddler.

Followup to this painting: [Oh You Poor Thing]

The Prodigy kids are so interesting to learn to draw. They have quite complicated color pallettes and designs that don't trivially translate to a 2D cartoon, and figuring out where to simply things without them being unrecognizable was an interesting challenge. I went for something close to the Lower Decks style this time (i.e., my usual Guzcomic style) to complete the crossover. If I ever made more Prodigy-focused comics I think I would first spend a lot of time coming up with a better simplification of their designs and color palletes. If there's one thing that the Prodigy kids absolutely have going for them, it's strong shape language in their silhouettes.

I really hope Prodigy gets picked up. I've been rewatching it and it's just so much fun.

Image ID: Digital art webcomic in a Star Trek Lower Decks like art style.

Panel 1: The alien kids from Star Trek Prodigy are wandering together in a crowd. Dal and Gwyn are calling out Murf's name. Gwyn has turned her liquid metal sword into a bullhorn. Zero says "Come out, come out, wherever you are!" Rok-Tahk says "Where are you..." Jankom, frustrated, says "Come on guys, it's no use. He's gone forever."

Panel 2: Eaurp Guz, a green slimegirl in a yellow starfleet engineering uniform, is running through the crowd with something wrapped up against her chest, holding it like a baby.

Guz: "Hello? Have you seen a--" Stranger 1: "No." Guz: "Have you seen a group of Mellan--" Stranger 2: "No thanks." Guz: "GRR! You'd think another Mellanoid Slime would stand out in the crowd." Guz: "Hello? Have you seen--" Stranger 3: "BEGONE FOUL THING!" Guz: "Ugh."

Panel 3: Guz continues. "Oh! you kids! Have you seen a Mellanoid Slime? Kinda like me. Gooey, sparkly, probably humanoid and bluish?

The Prodigy kids are gathered in a group and look at Guz, a little clueless. "Like Murf?" Dal says. "Who?" Guz says. The viewer can see Murf, the bluish-purple Mellanoid Slime Worm, being cradled by Guz, but the kids can't see him.

Panel 4 & 5: Close-up of the wrapped up Murf, who turns around, a little teary-eyed, and makes a chirp sound.

Panel 6: Murf leaps out of the wrapped blanket towards the kids, smiling, splashing some blue slime onto Guz's face, and she closes her eyes and braces for the goo to hit her. The kids look ecstatic. "MURF!" they all shout at once. Rok-Tahk goes on and says "I missed you." Jankom says, "Hah. Jankom never doubted a thing."

End Image ID.

extra:

Guz: so. you're. this slime worm's communal family.

Jankom: what of it, ya bag of snot?

Guz: do. do you even know how to raise a slime worm?

Dal: Yes! Well. Maybe. I mean he's basically indestructible, how hard could it be?

Rok-Tahk: Yeah! He once survived eating a live photon grenade.

Guz: What.

Dal: Yeah you know it was probably all the time he spent enslaved in the chimerium mines; hardened him up to it.

Guz: WHAT?

Gwyn: It's a long story.

Guz: wait. hey aren't you those wanted fugitives?

Jankom: Desperately, desperately wanted!

Zero: I can't read her thoughts but I do not think that's the kind of wanted she means.

"oh you poor thing, your family must be worried sick. You must be freezing. Let's get you wrapped up. WHO LEFT THIS TODDLER ALL ALONE IN SPACE?"