[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/ds9_alternate_229.jpg]]
[[caption-width-right:350:Dr. Mora Pol, who's overjoyed to see Odo again, and Odo, who's kind of the opposite of that.]]
Quark is selling the desiccated remains of a famous Ferengi, per his people's traditional death ritual, until Odo confronts him and reveals that the "dead" Ferengi is actually very much alive. As Quark awkwardly demands a full investigation, Odo gets a special visitor. Dr. Mora Pol, the researcher who discovered and educated Odo in his early existence, has come for a surprise visit. Odo is embarrassed by Mora's presence and quickly flees to his office. Mora peppers him with questions and marvels at how self-sufficient he's become. Then he spills his reason for his visit: He's discovered a planet six light-years from the wormhole in the Gamma Quadrant with possible evidence of where Odo came from.

After requesting a runabout from Sisko, Odo and Mora head off with Dax and a researcher named Dr. Weld Ram. Along the way, Mora tells Dax stories about first discovering Odo was a sentient organism much like a parent would tell embarrassing stories about their child's upbringing. Dax listens in amusement, while Odo can barely contain his annoyance.

Beaming down to the planet, they poke around the general area and find a monolith with unidentifiable writing on it. Dr. Weld also finds an metamorphizing organism possibly related to Odo. When the monolith is beamed aboard the runabout, the area is rocked by a massive quake.

Running to get clear of the collapsing rubble, the four are hit by an erupting column of poisonous volcanic gas. Odo seems unaffected (due to not possessing a respiratory system) and helps beam everyone back to the runabout.

With the others confined to sickbay, Odo pops in on O'Brien examining the organism Dr. Weld retrieved. O'Brien can't figure out what the frigging thing is due to it constantly changing. Just to be safe, the creature is locked in a level-5 containment field. Even still, the lab is found trashed the next morning, with the organism appearing to have escaped containment.

O'Brien heads into the vents to see if the thing escaped up there. After hearing a noise, he finds the thing alright. But it's dead. That appears to be the end of it. Until Bashir is attacked in his lab that night by a mysterious, tentacled blob creature. He drives it off with a laser scalpel and calls security.

And that's where things get odd. After an analysis, Dax confirms the dead life-form and whatever attacked Bashir can't be the same thing. Dr. Mora examines the evidence and rushes off to find Odo and deliver some terrible news: The thing that attacked Bashir ''is'' Odo.

Odo denies it. The attacks came while he was in his liquid state, and he has no memory of perpetrating the crimes. The two enter into a heated discussion that comes to a head when Mora demands Odo return to the research center with him. Odo begins to lose his structure and eventually turns into the beast that attacked Bashir when his emotions overcome him.

It turns out the gas that incapacitated the other three had an effect on Odo after all. Mora beats a hasty retreat from security and quickly formulates a plan with Sisko, volunteering himself as bait to draw the confused Odo-creature out and trap him in a force-field.

Odo takes the bait as a massive, misshapen, howling blob creature of pure rage. After futilely slamming into the field a few times, Odo manages to compose himself and return to his standard form.

In the infirmary later, Bashir states that the gas has been purged from Odo's body. He and Mora patch things up. Mora asks for permission to visit Odo from time to time, and Odo accepts.
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!!Tropes

* AbusiveParents: Even though Odo adamantly insists he doesn't consider Mora a father figure, they still very much have the dynamic of an abusive parent-child relationship. The physical elements of it (i.e., torturous experiments) at least stopped once Mora was forced to realize Odo was sentient, but Mora still constantly belittles and talks down to him, in addition to trying to manipulate him back into the lab by claiming Odo would be nothing if not for him. It's very telling about Odo's feelings towards him that the first thing he does when under the influence of the gas is repeatedly try to kill him.
* AmazinglyEmbarrassingParents: Odo is extremely embarrassed for Mora to interact with anyone who knows him. Sure enough, Mora seems poised to share some embarrassing story about Odo's upbringing to anyone who will listen.
* AsYouKnow: Odo explains the Ferengi death ritual to Quark in case any audience members haven't seen the previous episodes that introduced them.
* BodyHorror: The gas makes Odo turn into a large, rapidly shifting blob monster, incapable of anything more than bizarre snarling noises. During the initial stages, it looks like he's ''melting''.
* CompactInfiltrator: Thanks to its liquid body, the creature sneaks about Deep Space 9 via the ventilation shafts, allowing it to launch surprise attacks and disappear just as quickly.
* ContinuityNod: [[Recap/StarTrekDeepSpaceNineS01E17TheForsaken Odo said that he modeled his "hair" after the scientist who studied him]]. Mora shows up with the exact same hairstyle as Odo.
* EarlyInstallmentWeirdness: When Sisko reminiscences about his father's illness, we can assume his father is dead. However, Joseph Sisko turns up alive and well in fourth season's "Homefront".
* EasilyForgiven: Bashir is a pretty good sport about Odo attacking him, because Odo was NotHimself.
* EverybodyLives: Despite Odo turning into a rampaging monstrosity, nobody gets killed because of it. In fact the only casualty of the episode is the lifeform found on the planet, and whether that counts as a being is kind of nebulous.
* GenreShift: Deep Space 9 does horror. Dr Bashir even gets attacked after going to investigate a strange noise in the lab.
* HeelRealisation: Mora realises that he really was trying to keep Odo caged up as his lab experiment.
* JekyllAndHyde: Odo doesn't know that the monster he's trying to track down is actually himself.
* {{Jerkass}}: Doctor Mora spends much of his time talking down to Odo, interrupting him and then condescendingly talking about his formative years. He's even surprised and outraged that Odo, somehow, doesn't want to go back to the science lab he spent his "youth" in. Mercifully, he does get over it. In fact, one might notice that many of Mora's own more rough edges and superior attitude are echoed in certain attitudes of our favorite shapeshifting constable (including that tendency to imperiously cut in on people).
* TheKillerInMe: Odo is horrified to learn that he's the monster that everyone's looking for.
* MadScientist: Odo expresses bitterness about some of the experiments Mora conducted on him before realising he was a sentient being.
* MyGodWhatHaveIDone: Doctor Mora nearly says this word for word on seeing Odo's twisted form imprisoned by the forcefield.
* NightmareFetishist: At the beginning of the episode, Odo tells Quark he's got an interest in death rituals.
-->'''Odo:''' Everyone has a hobby.
* OneWingedAngel: Odo's bestial form is most assuredly this.
* ReverseThePolarity: O'Brien says they can do this to some energy fields to trap Odo.
* RiddleForTheAges: What was up with the monolith, and what was its connection to the changelings, if any? We never learn.
* SeriesContinuityError: Sisko's comments to Odo about his own father implies that he had since died, even though later episodes would show Joseph Sisko alive and still running a restaurant in New Orleans. (Albeit with health problems that may be related to the illness mentioned in this episode.)
* SoProudOfYou: Mora is proud of Odo's police abilities.
* WellDoneSonGuy: Odo spends most of the episode vehemently insisting that Dr. Mora is not his father and that he has no genuine connection with the man. However, any time Mora genuinely praises Odo for something he himself takes pride in, the subdued looks of shock and longing on Odo's face indicate that he's in denial about being this.

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