Remember how SG-1 took matters into their own hands last episode?
Well, they blow up Apophis' motherships, thereby [[UpToEleven single-handedly stopping an alien invasion of Earth.]] At least they didn't try to [[ShoutOut upload a computer virus.]]
!!"The Serpent's Lair" provides examples of the following tropes:
* AdamAndEvePlot: Invoked by the alpha site, where earth's "best and brightest" are sent when it appears that planetary destruction is imminent.
* AffectionateNickname: O'Neill greets Daniel with a fond and relieved "Spacemonkey" on the realization that he made it off the ship.
* AndMissionControlRejoiced: The control room at the SGC bursts into spontaneous cheering and applause when the ships explode.
* AppleOfDiscord: This was Bra'tac's plan before SG-1 showed up and effectively derailed it; to attack Apophis in Klorel's name, hoping that Apophis would assume Klorel had betrayed him and return fire.
* BearHug: O'Neill gives a ''big'' one to Daniel on finding him alive and well at the end of the episode after having been forced to leave him suffering a fatal injury on a ship that later exploded. Carter is only slightly more restrained when she gets her turn.
* BigNo: Apophis when he realizes the shields have been compromised.
* BlindedByTheLight: The Goa'uld shock grenades do this, in addition to emitting a deafening whine and rendering anyone in the vicinity unconscious.
* BrickJoke: In a callback to [[Recap/StargateSG1S1E11Bloodlines "Bloodlines"]]:
-->'''Bra'tac:''' We shall have to cross that bridge when we come to it.
-->'''O'Neill:''' You know, that particular cliche doesn't... always work.
* TheCavalry: The shuttle ''Endeavor'' showing up at the end when the heroes are drifting towards earth in crippled death gliders.
** The above-mentioned shuttles, which are mentioned as throwaway joke partway through the episode before appearing the save the day.
** The sarcophagus, which Daniel is able to uses to save his own life after it revives Klorel near the beginning.
* ContinuityNod: Bra'tac greets Hammond by referring to him as "Hammond of Texas" and gesturing to his head; in [[Recap/StargateSG1S1E11Bloodlines "Bloodlines"]] O'Neill described the general as "a very good man. A very ''bald'' man. From Texas."
* DeathIsCheap: Klorel/Skaara is resurrected in the sarcophagus after being killed by O'Neill in the previous episode.
* DirtyCoward: Once it becomes clear that earth is defenseless against Apophis' forces, Colonel Samuels asks to be taken to the alpha site. Hammond denies his request, as they are [[TakeThat only sending the best and brightest]].
* ExplosionsInSpace: When the ships are blown up.
* FaceDeathWithDignity: Subverted:
-->'''O'Neill:''' Now what?
-->'''Bra'tac:''' Now we die.
-->'''O'Neill:''' Well that's a ''bad plan''. Where are the glider bays from here.
* FightingFromTheInside: Skaara is shown to be fighting Klorel's influence, and is even able to assert some control for brief periods of time. Apophis is not happy when Klorel admits this.
* FinishDialogueInUnison: Daniel and O'Neill lapse into this when Bra'tac inquires about earth's "warships".
-->'''Bra'tac:''' Surely you have such vessels?
-->'''Daniel:''' We have a number of... of...
-->''' Daniel & O'Neill:''' ...shuttles.
* GunsAkimbo: Daniel again, this time wielding the Beretta in one hand and Carter's MP5 in the other. Though it's something of a subversion in that he's firing wildly and doing more damage to the walls than anything else, with the overall effect seeming more desperate than badass.
* HeroicBSOD: Daniel has a brief moment of this when the team is captured and temporarily blinded.
-->"We're blind and we failed."
-->'''Bra'tac:''' We die well, Teal'c.
-->'''Teal'c:''' Better than that, old friend. We die free.
** Also said earlier in the episode by Bra'tac when Klorel was using the [[AgonyBeam hand device]] on him.
* IWarnedYou: Samuels has an "I told you so" moment when he insists that if Hammond had listened to his warnings about the stargate from the beginning, they wouldn't now be facing the threat of annihilation. Later inverted when Samuels' plan to destroy the ships fails epically, though Hammond is too big a man to actually say anything.
* IWillOnlySlowYouDown: Daniel insists that O'Neill leave him behind when he's mortally wounded, pointing out that he's going to die anyway and at least this way he can watch their backs.
* ManBitesMan: Carter bites O'Neill's hand, mistaking him for an attacker when tries to wake her up after they've all been blinded by the shock grenade.
* NoOneGetsLeftBehind: [[SubvertedTrope Subverted;]] O'Neill reluctantly leaves Daniel behind at his request. Ironically, it's implied that he would have died if they ''hadn't'' left him; he was fatally wounded, but by staying on the ship he was able to use the sarcophagus to heal his injury and then use the stargate to get back home.
* NoSell: The new naquadah-enhanced warheads fail to even make a dent in Apophis' shields.
* ReverseMole: Bra'tac had been working as one among the ranks of Klorel's Jaffa.
* SpannerInTheWorks: From Bra'tac's perspective, SG-1 is this, showing up at the worst possible time and derailing his plan to play Apophis and Klorel against each other.
* StatingTheSimpleSolution: When Bra'tac launches into a lengthy technical explanation of how they can climb down a shaft to disable the shields, O'Neill responds by taking out a grenade and simply dropping it down the shaft.
* SuicideMission: The mission started in the previous episode turns into this when the team realizes that the ships are ready to start attacking earth. Subverted at the end, however, when O'Neill suggests they try and make their escape instead of hanging around waiting for the explosion.
* TemporaryBlindness: The effect of the Goa'uld shock grenade.
* VillainExitStageLeft: Apophis and Klorel promptly [[ScrewThisImOuttaHere abandon their ships on realizing that they're about to explode.]]
* YouShallNotPass: Daniel initially plans to pull this, but when he isn't met with any resistance he drags himself to the sarcophagus instead.