"It makes me ill that I was forced to pretend to be your friend. So many times I had to save your life when I wished I could watch you die."
— Teal'c
O'Neill, Carter, Daniel and Jacob are still stranded in a distant galaxy facing down Apophis when a mysterious ship turns up to intervene. Things take a turn for the worse when the ship turns out to be full of replicators, and Teal'c reappears only to reveal that he's been brainwashed into believing that he is still in the service of Apophis.
"Enemies" provides examples of the following tropes:
- Always a Bigger Fish: Apophis is about to decimate the heroes when a replicator ship appears out of nowhere to attack him, giving them time to get away.
- Bearer of Bad News: The Tok'ra High Councilwoman visits the SGC to inform Hammond that SG-1 and Jacob are MIA.
- Big "NO!": Apophis's last words as the ship hurtles uncontrollably toward the surface of his planet while replicators crawl all over his personal shield.
- Bittersweet Ending: Apophis is finally dead, the replicators are destroyed and the team manages to make it back to their own galaxy, but Teal'c is still suffering from the effects of the brainwashing and believes himself to still be loyal to Apophis.
- Body of Bodies: The two variations of replicator bugs snap together into a giant super-bug to act as a secondary power source for the ha'tak hyperdrive, allowing the ship to move many times beyond its normal maximum speed. When O'Neill shoots out the sublight control crystals so the ship will crash, the super-bug immediately breaks apart into its constituent bugs and the swarm gives chase.
- Brainwashed and Crazy: Since capturing Teal'c in the previous episode, Apophis has brainwashed him into believing that he never left Apophis's service and the last four years have all been part of some elaborate long-con. The rest of the team is quick to point out how very little sense that makes.
- Continuity Nod:
- Daniel reminds Teal'c of the time Apophis brainwashed his son, imploring him to consider the possibility that something similar has happened here.
- The team deal with replicators using a similar method to how they destroyed the ones infesting the Beliskner in "Nemesis"; by sabotaging the ship's sublight engines and preventing it from being able to slow its descent, forcing it to crash into the surface of Apophis's planet.
- Everybody's Dead, Dave: O'Neill, Carter and Jacob board Apophis's mothership to find all his Jaffa dead and the ship crawling with replicators.
- Exact Words: When Teal'c contacted the ship O'Neill, Carter, Jackson, and Jacob were on, he merely said he escaped the mothership with Jaffa who agreed with his cause. The team assumed it was their cause, but being Brainwashed and Crazy, Teal'c meant it to be the cause of Apophis and used those exact words to be allowed on their mothership.
- Finishing Each Other's Sentences: The Carters lapse into this when explaining their plan to defeat the replicators.
- Foreshadowing: This is the very first time the Goa'uld and Replicator storylines converge...and it won't be the last...
- Goa'uld technology and weaponry is no more effective against the Replicators than Asgard technology or weaponry has been. This too will be important down the road.
- From Bad to Worse: Following the events of the previous episode, the team start out stranded on a crippled ship in a distant galaxy, alongside Apophis, who is preparing to fire on them. A mysterious ship then appears out of nowhere to "rescue" them, which they consider to be a blessing until they board Apophis's ship to steal his control crystals and find it teeming with replicators. Then it emerges that Teal'c managed to escape the carnage and asks to be brought aboard the heroes' ship, only for it to turn out that he's been brainwashed into believing he still serves Apophis and has brought with him a small platoon of Jaffa, plus Apophis himself... and then to top it all off, it turns out they inadvertently brought some replicators along for the ride, allowing them to quickly take over the ship. So to recap, the team ends up four million light years off-course, held prisoner by Apophis on their own ship, which is now infested by replicators, and fighting against one of their True Companions.
- The Guards Must Be Crazy: Subverted; Jacob is able to spring the others from their holding cell as there are no guards stationed outside, but it turns out that this was all part of Teal'c's plan to capture Jacob and he promptly orders him inside with the others.
- "I Know You're in There Somewhere" Fight: O'Neill repeatedly tries to do this to Teal'c, with little success.
- Insane Troll Logic: Used in-universe, when Teal'c is brainwashed to believe he never left the service of Apophis. He comes up with ridiculous explanations when Jack points out that he helped SG-1 take down Apophis twice, and watched him die once.
- Killed Off for Real: Apophis is finally, definitely taken care of once and for all. Maybe.
- Know When to Fold 'Em: Daniel tries to surrender to Apophis at the beginning of the episode, hoping to buy some time before Apophis destroys them. It doesn't do much good, however, as Apophis simply replies that they're too late before preparing to fire anyway.
- Lock-and-Load Montage: O'Neill, Carter, Daniel and Jacob get one of these when they manage to escape from the hold and find where their weapons have been stashed, prompting them to strap on a P90 each in preparation to do battle with the replicators.
- Offhand Backhand: Teal'c offhandedly punches O'Neill in the face as the latter is standing over his shoulder, trying to talk some sense into him.
- Oh, Crap!: Apophis gets a big one as the replicators begin to swarm into the pel'tac towards the end.
- Outside-Context Problem: The Replicators are this to both Apophis and to Jacob/Selmak. SG-1 specifically has to brief the latter on the dangers of letting them gain a foothold in the Milky Way.
- Prepare to Die: Apophis says something to this effect as he prepares to fire on the team.
- Running Gag: O'Neill snarking at Jacob for his — justifiably — negative attitude is something of a recurring theme throughout the episode.O'Neill: Excuse me. I distinctly remember someone saying, "We're not going to make it." I think we made it.
Jacob: I'm sorry, I over-reacted. At the time, it looked very much like we weren't going to make it. - The Swarm: O'Neill, Carter and Daniel manage to piss off a very large swarm of replicators when they take out the ship's sublight engines, resulting in the three of them running for their lives to get to the ring room while firing wildly at the oncoming horde.
- There Is No Kill Like Overkill: For both Apophis and the Replicators. SG-1 leaves them all to die on an out-of-control Ha'tak that's about to crash right into Sokar's old capital world at full speed. The stratagem is completely justified between knowing how difficult the Bugs are to kill and ensuring that this time Apophis can't pull a Joker Immunity for the umpteenth time.
- Villainous Rescue: The replicators "save" the team from imminent death by Apophis at the beginning of the episode.
- We Have Reserves: Apophis allows his Jaffa to meet their deaths in a futile battle against the replicators while he swiftly exits the scene.
- You Are in Command Now: Despite being the least qualified person for the job, Daniel is left in command of the team's ha'tak when the others board Apophis's ship to salvage the control crystals. Jacob hangs a lampshade on this when he quips that they've obviously left him in charge too often after Daniel starts giving out orders.
- You Did Everything You Could: Daniel tries to reassure O'Neill of this while they still believe Teal'c to be dead and O'Neill is in the midst of blaming himself for his capture on Vorash.
