Stargate SG-1/Recap/S6 E16 Metamorphosis

The Russian SG team returns through the gate with a captive from the planet they have been visiting. After O'Neill and General Hammond both yell at them for a bit for violating procedure, they agree to listen to the man's story. His name is Alebran and he claims that his people are being experimented on by the Goa'uld Nirrti. He begs the SGC for help against her, and then dissolves into a puddle of water because of a failsafe Nirrti built into his very DNA.

Figuring that she is continuing her experiments to advance human evolution and thereby create the perfect host, SG-1 decides to investigate. When they get there, however, they find that Alebran's horribly mutated and hideous people do not want to be liberated. They consider Nirrti to be their savior (from a plague that ravaged their civilization) and worship her as a God. They have also developed superhuman abilities - telekinesis and telepathy in particular - and have SG-1 and Col. Ivanov of the Russian team locked up in short order. All the better for Nirrti to experiment on.

One at a time, Nirrti plugs the captured team members in to her DNA scanning machine and futzes with their biology. Ivanov is first, followed by Carter. When it comes around to Jonas's turn, however, Nirrti apparently sees something she likes. He wakes up in her personal quarters, where she reveals that he is far advanced in his evolution, and offers him unlimited power if he will join her. When he systematically refuses to put out, she tosses him back into his cell, just in time to see Col. Ivanov dissolve into a puddle of water.

While Jonas was away refusing to be seduced, O'Neill has been trying to convince the mutants that Nirrti is bad news. He argues that if they just read her mind (which happens to be forbidden) it will confirm everything he's said. It needs to be quickly too, because Carter is beginning to look pretty moist. They ignore him and drag him off to have his DNA manipulated. He trades his usual banter with Nirrti for a while, and again tries to get the locals to look into her mind. This time, they do - and realize that she's an evil monster, just as O'Neill has been saying this whole time. With their telekinetic powers, they rescue O'Neill and kill Nirrti - which is bad, because Carter is going to melt into a pile of goo any minute now.

Fortunately, they also managed to steal Nirrti's knowledge of how to operate the machine. The restore Carter in short order, and then themselves, saying they will destroy the machine once they are done.

Jonas is probably fine.

Tropes

 * Body Horror
 * Evilutionary Biologist
 * Mutants: Alebran's people, of the mutate variety.
 * We Can Rule Together: Nirrti to Jonas