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This episode is part 2 of 2; it is preceded by "Instinct".
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"Conversion" is the eighth episode of the second season of Stargate: Atlantis.


After some of the Iratus bug retrovirus transferred from Ellia to Lt. Colonel John Sheppard, he starts to experience side affects that is quickly turning him into a cross between a Human and an Iratus bug. Dr. Carson Beckett must work on a way to save him before it is too late.

Previously on Stargate: Atlantis

On a mission to the Wraith homeworld, Major John Sheppard is attacked by an Iratus bug. A year later, the team meets Ellia, a female Wraith that was raised by a Human named Zaddik. Ellia takes Dr. Carson Beckett's incomplete Iratus bug retrovirus and turns into a creature closer to an Iratus bug. Sheppard and Ronon Dex manage to kill her but she feeds on Sheppard's arm.


The episode continues the events from the previous episode "Instinct", in which Lt. Colonel John Sheppard was wounded by Ellia after she mutated. He is brought in the infirmary although he doesn't think this is necessary. His wound is treated but it turns out that it completely healed, much to the surprise of Dr. Carson Beckett. The two speculate what could have happened and while Beckett analyzes the blood sample, Sheppard leaves. He later runs against Ronon Dex and is much quicker than him, which surprises the two. Later he trains with Teyla Emmagan who he also easily defeats. However he then pins her against the wall and kisses her. Surprised, he leaves. Later Sheppard meets with Dr. Elizabeth Weir and Beckett, who reveals that he is infected with the Iratus bug retrovirus, because of the wound from Ellia. He is thus removed from duty and ordered to return to the infirmary every six hours.

At night, Weir meets with Colonel Steven Caldwell who talks with her about Sheppard. He tells her that he wants to take over Sheppard's duties and she tells him that she will think about this. Meanwhile Sheppard enters his room and when he looks at his arm it turns out that he is starting to mutate. The next day he is scanned by Beckett who reveals that he is mutating into a creature similar to Ellia, which will happen within a matter of days. Although Beckett can't stop it, he injects Sheppard with a viral inhibitor which slows down the virus in his brain. Sheppard then wakes up and tells Weir that he feels like Lt. Aiden Ford must have felt while on the Wraith enzyme.

Later the doctors at Atlantis discuss what to do and Beckett points out that they should use Iratus bug stem cells to attack the virus from the inside. However the cells they have are too old to be used so they need new. Meanwhile Weir meets with Caldwell and tells him to take over Sheppard's duties but he proposes some changes which she doesn't like. Later she discusses with Dr. Rodney McKay, Beckett and Major Evan Lorne the plan to get stem cells from Iratus bug embryos and although it's a dangerous mission she allows it. Afterwards Sheppard visits her he wants on this mission but she doesn't allow it so he angrily crashes the glass of her office.


On a planet Lorne's team finds a cave full of Iratus bugs and enters it. On Atlantis, Weir talks with Sheppard whose mutation continues and so he proposes a stronger security at his room. Back on the planet the team finds a large room in the cave full of bugs but when Beckett tries to get to the embryos they attack. They are forced to flee but two members of the team are killed so Lorne ends the mission. Back at Atlantis Weir informs Sheppard who wants them to try again. When she refuses he attacks her and then escapes his room. The others then try to capture him but he moves very quickly and is unharmed by the Wraith weapons which should stun him. He then defeats a team and flees before Teyla can capture him, but Ronon finally stuns him with his particle magnum. Sheppard is then put into a medically induced coma, but in 24 hours the virus will have taken him over completely.


Later Beckett finds out a way to probably help Sheppard. He proposes sending Sheppard to take the embryos because he produces signature pheromones of the bugs so they won't attack him. By injecting him an overdose of viral inhibitor he would have one hour to act. Weir then allows the mission and Sheppard goes with his team to the cave. He is able to get the stem cells but then storms out of the cave and is stunned by Ronon.

Back at Atlantis Beckett tells the others that the transformation has begun to reverse itself which will however take some time. A few weeks later, Sheppard has become himself again and so he visits Teyla. He tells her that he started to remember things about what has happened during the time that he wasn't himself and that he wants to say sorry but she tells him to forget it. However, Teyla calls Sheppard "John" as he'd told her to during the incident in the gym.


Atlantis conference room; Atlantis database; Atlantis infirmary; Atlantis living quarter; Atlantis transporter; Bantos fighting; Biometric sensor array; Blood; Steven Caldwell's office; Chess; Daedalus; DNA; Ellia; Evel Knievel; Flare; Fragmentation grenade; Lt. Aiden Ford; Hermiod; Iratus bug; Iratus bug retrovirus; Night vision goggles; Lindsey Novak; Particle magnum; Pheremones; Planet (Conversion); Runner; Salt; Skirmish with the Daimos; Solitaire; Sparring; Stem cell; Wraith; Wraith stunner rifle

Notable Quotes

(Beckett is wheeling Sheppard into the Infirmary on a gurney)
Sheppard: This really isn't necessary, Doc.
Beckett: Yes it is, you've got a serious laceration on your arm and you've lost a good deal of blood.
McKay: Well enjoy the ride, Colonel, they're making me walk.
Beckett: You have a splinter Rodney.
McKay: Yeah, a nasty, painful splinter.

(Beckett and a team of scientists are working on a way to cure Sheppard. Beckett suggests gene therapy)
Biro: I have no doubt that we could program the cells if we had them, but we don't have the time to artificially create gene therapy of that magnitude without newer cells. The only samples we have are from a bug that died over a year ago.
Beckett: Which means, ladies and gentlemen, that we need to go on an egg hunt.

McKay: Maybe we should make a diversion.
Lorne: Are you volunteering?
McKay: I'll shut up.

'(Before entering the cave full of iratus bugs McKay zips his collar up)
Beckett: You don't seriously think that's gonna help do ya?
McKay: Well, when they see your neck before mine, you won't think it's stupid.
(later Beckett zips up his jacket before going to collect eggs)
McKay: See, not so stupid now is it?
Beckett: Oh shut up.

Weir: John? So, this is when I usually ask you a stupid question, like how are you feeling. John? John? Our team got back from the mission.
(Sheppard suddenly appears behind her, the retrovirus extremely advanced)
Weir: The nest was too well protected. We were unable to retrieve the eggs. They tried their best.
Sheppard: Best?
Weir: The bugs attacked.
Sheppard: Try again.
Weir: I can't do that.
Sheppard: Why?
Weir: John...
Sheppard: No.
Weir: I understand-
Sheppard: If you won't, then kill me now.
Weir: John...
Sheppard: It's better for the both of us.
Weir: I can't do that.
Sheppard: Then try again.
(Weir shakes her head no. Sheppard grabs her by the throat and puts her up against the wall)
Weir: We lost Walker and Stevens. I won't send another team. I won't risk more lives.
(Sheppard drops her and leaves the room, taking out the two guards at the door)
Weir: This is Weir, we have a security breach. Colonel Sheppard's quarters.

Weir: How are you?
Sheppard: My body's mutating into a bug. How are you?

Sheppard: Did Ronon shoot me?
Weir: You had it coming.


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Stargate Wiki has 16 images related to Conversion.
  • Rachel Luttrell (Teyla Emmagan) voiced the "previously on Stargate: Atlantis" line.
  • This episode was actress Rachel Luttrell's first on-screen kissing scene.[1] According to the DVD audio commentary for this episode, her parents were present for the kiss.
  • In the scene when Lt. Colonel John Sheppard is being tracked by Atlantis, there is a dot indicating his position. Next to the dot, there is a text "for (int n=0;n<col;n++) // normalize remaining value to 1", a first line of the code of for loop and a comment.[2]
  • Some of the items in Sheppard's quarters were brought in by actor Joe Flanigan, including the skateboard, surfboard and the picture of his younger self with Evel Knievel which is displayed at the side of the bed.
  • Teyla's "do not make me do this" to Sheppard perched above her on the stairs is a near-direct replay of the previous episode, where Sheppard said "don't make me to this" to Ellia perched on a tree limb above her.
  • Todd Hann (Bravo Leader) previously played Sgt. Gibson in the Stargate SG-1 episode "Prometheus".
  • Matthew Harrison (Scientist) previously played Darian in the Stargate SG-1 episode "Double Jeopardy".
  • This episode takes place over the course of more than two weeks.
  • The scene where Sheppard beats Teyla with bantos rods one-handed is somewhat similar to the finale scene in The Matrix where Neo beats Agent Smith one-handed (although that fight is hand-to-hand).


  • When Dr. Carson Beckett radios Dr. Elizabeth Weir to meet her in her office he is wearing his lab coat. When he arrives in the control room he has changed to his expedition jacket. Then he changes back into his lab coat when he returns to the Atlantis infirmary.
    • Often it's not allowed for medical personnel to leave the infirmary with their lab or OR clothes.
  • When the team arrives at the beginning of the episode, it's meant to be a direct continuation from "Instinct" (as Lt. Colonel John Sheppard is still bleeding). Beckett, however, is on Atlantis in his regular uniform, despite being offworld and in BDUs at the end of "Instinct."
  • It would be logical to wear some protective gear while around Iratus bugs.
  • The Daedalus could have easily traveled to an Iratus bug planet, and beam the eggs to the ship.
    • It would have been difficult or impossible for the transporter's scanner to discern the eggs from the bugs. It is stated repeatedly on Stargate SG-1, that too many (small) life signs make locking to a specific target difficult.
  • The fire explosion caused by the grenade in the cave is unreasonably large, even for Hollywood standards.
    • Not really. The fireball of a standard military grade hand grenade can be up to 5 m in diameter, especially if detonated in close spaces, shrapnel up to 15 m. In most Hollywood movies, hand grenade detonations are way too small. A good example of this understating are the claymore mine explosions on Stargate SG-1.
  • When Sheppard is walking across the Iratus bug cave, you can see that he steps on one of the CG Iratus bugs.
  • When Sheppard fills the container with eggs, it's so full the eggs are threatening to overflow and spill out. However, once he gets outside and Beckett takes a look inside, it looks as if it's empty, even if it's from an odd angle. If it was so full, at least some eggs should be visible at the top.
  • Hyperdrive engines are not referred to as "FTL" drives until Col. Caldwell mentions it in this episode. Despite whilst still being technically correct, it may be a dig at its use in Battlestar Galactica.
  • Given the nature of Sheppard he should have been placed in the Atlantis Brig rather then in a room which he could leave by himself.
  • Stasis could have been used at any point to halt Sheppard's mutation.
  • When Sheppard was on the loose the Daedalus could have easily just beamed him up and into a holding cell or the Atlantis Brig.
  • While discussing using an iratus bug stem cell treatment, one of the doctors comments that the only samples they have are from an iratus bug that died over a year ago. This bug, the one that attached itself to Sheppard in "Thirty-Eight Minutes" was blown into space so there should be no samples from it.
    • They would most likely have acquired at least some iratus bug cells from the wound it inflicted on Sheppard.

In Other Languages

  • Russian: Превращение (Conversion)
  • Hungarian: Átváltozás (Conversion)


  1. Gosling, Sharon. Stargate Atlantis: The Official Companion Season 2. 2006. Titan Books. London. ISBN 1–84576–163–4. Page 53.
  2. John Sheppard's source code from Univesity of Minnesota Methods of Experimental Physics Laboratory. [1]

External links