The ship's captain, who encounters an old flame after his crew gets stranded in a remote repair station.

• Adaptational Nice Guy: Thom is married in the short story and ends up sleeping with Greta while hiding her existence from his wife (or so he thinks he's doing). In the episode, there's no mention that he's married.
• Ambiguous Situation: While it's clear that Thom is trapped in a simulation for most of the episode and at the very end, it's not clear if the "reality" he sees when he demands to be let in on what's going is truly reality or if it's a simulation meant to reflect it. Greta's exact words are that he's still asleep in his cryo tank.
• Did You Just Romance Cthulhu?: He spends weeks dating and having sex with "Greta", who's actually the avatar of a grotesque spider-like alien capable of generating false realities within the minds of other creatures. It's unclear what the alien's feelings actually are in this situation, though.
• Hunk: He's a big muscular man who loses his shirt for a whole scene, and has a fun fling with an old flame. In "reality", he's long since been starved, leaving him bony and emaciated.
• Ignorance Is Bliss: At the climax, Greta insists that Thom can't actually handle his true situation. And she is right. Thom is absolutely horrified, so Greta knocks him right back out and keeps him in the pleasant reality scape, as Greta, seemingly intent on defying this by getting him to accept his new reality somehow.
• Really Gets Around: It really doesn't seem as though Greta was his only "fling", but it sure seems to be his best one. This is no coincidence.
• Spotting the Thread: There are multiple tiny glitches in the simulation, but the one that gets Thom's attention is that Greta's neck injury is gone in less than a day.
• Thinker Pose: Thom sits in a similar manner as the trope namer, in his bed, with a cigarette in his hand, after having sex with Greta.
  Greta: I always think men are sexier when they try and think.
• Through the Eyes of Madness: Thom's nightmarish reality where he's gaunt, dying of malnutrition, and witnessing a horrific spidery meaty nest is mind-breaking. What's not clear is whether this is him entering reality for a brief instance, or him being thrown into another simulation meant to reflect it as a litmus test for how he'd respond.

The ship's navigator.

• Only Sane Man: She's very well aware that Greta is not what she seems. Thom is blissfully oblivious, and Ray never actually wakes in Thom's dream. She either represents Thom's subconscious trying to warn him, or is another avatar used by Greta to urge him to face reality.
• The Smart Guy: She handles the navigation for the ship, which requires complex calculations, lest the ship is thrown off course.

The third crewman. Greta insists on keeping him on suspension.

• Killed Offscreen: After being let out of the simulation, Thom gets a look at his decomposing corpse.
• Shoo Out the Clowns: He's introduced complaining loudly of a hangover. After the ship is stranded, he's left in his chamber and plays no further role in the story.

An old flame of Thom. She's apparently in charge of the repair station Thom and his crew are stuck in.

• Adaptational Villainy: Downplayed. The original short story makes it unambiguous that the alien impersonating Greta has no ill-will or nefarious goals. That isn't the case here, making her morality more ambiguous though leaning towards being a genuinely empathetic caring alien.
• Ambiguously Evil: The whole situation seems a bit too suspicious to be coincidence. Greta, meanwhile, seems a bit too reluctant to tell Thom the whole truth. The ambiguity only gets stronger after the reveal of what Greta actually is. It's a horrifying eldritch creature that may or may not have caused the ship to go off course, but why is it so keen on keeping Thom happy?
• Anti-Villain/Anti-Hero: It's not entirely clear in the episode which one of these she is, though Word of God claims that she's good, putting her in the latter. She traps ships that have drifted into the void in her snare of meat moss, and traps the victims in a simulation to try to gently break the bad news to them. Her reasons for doing so aren't entirely clear.
• Apologetic Attacker: In a sense. She's deeply apologetic to Thom, claiming he's not ready to know the truth, but ultimately lets him see a vision of it (she says he's still in his tank, meaning he's never been "truly awake"), and reveals her true self. In this case, she's not even attacking directly, it's just that her very existence and appearance is not healthy for human minds, and she knows it.
• Bearer of Bad News: She appears to be trying to be a good and gentle version of this as possible. She starts by saying the victims have gone off course on their trip, then reveals that they're outside the limits of human travel capability, and then reveals that they're in a simulation. The one thing she has trouble revealing is the reality of the situation the victims are in: they're not in a mechanical space station, they're in a huge nest of Meat Moss.
• Benevolent Abomination: Deconstructed. The creator of the episode claims that she's in fact this, but the fact that she's extremely inhuman and only can experience humanity through encountering humans and effectively Mind Raping them, it doesn't really do her any favors.
• Bizarre Alien Biology: Her design alone should make this a rather clear example.
• Blue-and-Orange Morality: Despite claims to the contrary, Greta seems motivated solely by a desire to help the crew as best she can, a fact which is further illustrated in the novel where-in her ship was the first to crash. Even the creator of the episode says her intentions are good, though due to her alien nature the results may be unintentionally horrible.
• Contrived Coincidence: What are the odds of Thom finding her in such a remote station by accident? Turns out, it was no accident.
• Dead All Along: The reveal means the real Greta is long dead, seeing as "several hundred years have passed back home."
• Determinator: She seems to be determined to get Thom to accept the reality of his situation in some manner, given that she implicitly traps him in a cycle of simulations to break the bad news to him in a way that won't leave him broken-minded.
• Eldritch Abomination: No matter whether it's benevolent, "Greta" is a bizarre entity. She/It looks like a spidery alien with eyes near its "groin" area and has the power to ensnare any ships in the vicinity in its muscular tendrils along with psychic abilities to trap people in hallucinations.
• Exact Words: Right before letting Thom back into reality to let him see the truth, Greta says that he's in a simulation and specifically that he's still in his tank. This means that "reality" and the reveal of her true form is likely also a vision.
• A Form You Are Comfortable With: Greta knows that humans don't react well to the environment they've been landed in, the situation itself or her appearance, and so tries to very slowly make those unfortunate enough to crash at her station aware of their situation. However it seems her act or psychic power need work as she has 'gone through this a thousand times' and dealt with many 'lost souls' who all demands to see the truth and proceed to break from the experience, and in Thom's case upon seeing her.
• A Glitch in the Matrix: Her simulations aren't flawless. For one, her shadow betrays her (look carefully at the wall when Greta tells Thom he's in a simulation), and her true form can slip through the illusion (look at the liquor bottle when Thom and Greta are in the bar). When Thom gets agitated and physically pushes Greta, the entire simulation visibly glitches, revealing the muscle fiber tendrils that actually make up the station. The one that catches Thom's attention is that her neck cut sustained from Suzy is gone in less than a day.
• Impersonation-Exclusive Character: With the reveal that Greta is just the form the creature was using to ease Thom, the only things we know about the real Greta are what she looked like and what Thom and fake Greta said about her.
• Innocent Aliens: If taken at face value, Greta is a benevolent, if horrifying creature trying to care for the creatures that landed at her station. It's not entirely clear that she can be taken at her word; though it should be noted that there's no benefit to herself in caring for people like Thom, beyond the simple act of caring for them. It's not clear that she understands how to do this exactly, as Thom was reduced to a skeletally thin and pallid state in the real world, if that is in fact reality and not another simulation meant to imitate it.
• Mathematician's Answer: After forcing Thom back into a simulation, she approaches him and he asks "Greta" if it's really her there.
  Greta: (pained) It's good to see you, Thom.
• Ms. Fanservice: A gorgeous woman with a lot of emphasis placed on her during her and Thom's lovemaking. As mentioned above, it is not her true form.
• Save Scumming: She's tried to ease Thom into his situation, and when it was shown that he can't handle the reality of his situation, she started over by erasing his memories of the waking world and the previous simulation. Comments made by her after Suzy's awakening hint that she's tried this over and over many, many times. And Greta herself clearly has done this many times with numerous other individuals that happened upon her hive.
• Seductive Spider: She's a spider-like creature in her true form, but in her disguise she comes off as an attractive old flame of Thom. There's a Bait-and-Switch moment where her true form at first is teased to be a curvaceous humanoid alien...and then the rest of her comes into view.
• Starfish Aliens: Her true form appears to be a monstrous, oozing, many-eyed and many-legged entity vaguely resembling a gigantic, fleshy arthropod.
• Virtuous Character Copy: An entity that can read people's minds and trap them in hallucinations, and it relies on their compliance to its desires to maintain the illusion...and the creature's true form is something eldritch that can only vaguely be described as a spider and is associated with bright red and orange colors. Greta is ultimately a well-meaning version of Pennywise, operating on Blue-and-Orange Morality rather than malice.
• You Cannot Grasp the True Form: Her physical appearance is not like a typical Brown Note Being, but she's so horrific and her hive is so nightmarish in appearance that almost every living being who encounters her breaks when they see what she really looks like.