History Recap / StrangerThingsS4E7ChapterSevenTheMassacreAtHawkinsLab

* CutHimselfShaving: When Dr. Brenner asks the kids if anyone knew why Eleven suffered a concussion the night before (while she pretended to [[TraumaInducedAmnesia not remember]]), Two quips she must have fallen.

** She accidentally opened a hell gate when she kills One, setting up the events of Season 1.

* AttackItsWeakPoint: Once his flaming spearhead begins to die down, Hopper once again goes for the Demogorgon's relatively fleshy mouth, throwing the

* ThePowerOfHate: Once again, Eleven uses her anger about how she was abducted and her mother mistreated to channel her powers and defeat One.

-->'''Mr & Mrs. Sinclair:''': "ERICA!"

* BookEnds: The start and end of Eleven's journey to getting her powers back involves brutal, yet well-deserved LaserGuidedKarma to her tormentors: Angela gets punished for being an AlphaBitch with a sucker punch to the face with a rollerskate and Two gets punished for being TheBully with his death at the Orderly's hands.

* {{Foreshadowing}}: When describing the concept of the Upside-Down's HiveMind to Eddie, Steven summarises it as the Vines, monsters and creatures of the world all being 'like, One, or something', and that stepping on the vines is equivalent to stepping on Vecna and alerting him to their location. The episode ending reveals that all the creatures and monsters under [[HeWasRightThereAllAlong Vecna's]] control [[StealthPun are indeed]], [[YouAreNumberSix One]]

** Once his powers are restored, the Orderly, AKA One, commits the titular massacre. Even the telekinetic children are helpless against him, though it's not shown if Two was able to put up any sort of fight like Eleven was.

** Murray swiftly takes out four Russian guards with only his karate skills and the butt of his pistol.

* EvilCannotComprehendGood: One is genuinely surprised at El's horrified reaction to the massacre. He expected her to be glad the kids who shunned and bullied her were dead.

* {{Foreshadowing}}: When describing the concept of the Upside-Down's HiveMind to Eddie, Steven summarises it as the Vines, monsters and creates of the world all being 'like, One, or something', and that stepping on vine is equivalent to stepping on vena and alerting him to their location. The episode ending reveals that all the creatures and monsters under [[HeWasRightThereAllAlong Vecna's]] control [[StealthPun are indeed]], [[YouAreNumberSix One]]

* HoistByHisOwnPetard: In an earlier episode, One taught Eleven how to [[ThePowerOfHate fuel her psychic powers with anger]]. It ultimately becomes his downfall as it allows Eleven to defeat him.

* ActuallyPrettyFunny: When Robin and Eddie fall through the gate into the real world, they both admit that the experience of doing do was pretty fun.

* BaitAndSwitch: The Soviet commander tells Murray impersonating Yuri that he heard Yuri "had a screw loose", making it seem as though he's seen through the facade. Then he says that "Yuri" has "many screws loose" and starts laughing.

* BloodFromTheMouth: Steve after the fight scene with the flying bats.

* BoozeFlamethrower : Downplayed. Remembering the Demogorgon's only weakness is fire, Hopper steals a lighter and a bottle of alcohol and douses a spearhead.

* HoistByHisOwnPetard: In an earlier episode, 001 taught Eleven how to [[ThePowerOfHate fuel her psychic powers with anger]]. It ultimately becomes his downfall as it allows Eleven to defeat him.

* MisanthropeSupreme: 001 views humans as an infestation in an otherwise orderly world and wants to wipe them all out.
* MotiveRant: 001 delivers one to Eleven [[MisanthropeSupreme comparing humanity to a pest infesting the earth]], how human laws are oppressive and how human life is utterly mundane and pathetic.

** She accidentally opened a hell gate when she kills 001, setting up the events of Season 1.
** She unwittingly removed the RestrainingBolt from the orderly's neck who turns out to be 001, who then ran amok at the lab and later turns into Vecna, the BigBad of Season 4.

* ThePowerOfHate: Once again, Eleven uses her anger about how she was abducted and her mother mistreated to channel her powers and defeat 001.

* PreExplosionGlow: Same as done with the Demogorgon in the season 1 finale, 001 glows from the inside before getting destroyed by Eleven.

* RestrainingBolt: 001 has one implanted in his neck which once removed by Eleven turns him into a lethal killing machine.
* {{Retcon}}: The flashbacks to the massacre reveal that Eleven first opened a gateway to the Upside Down not during one of Brenner's experiments, but when trying to kill 001. Semi-justified as ''that'' gate was a permanent 2-way portal between the realms, whereas the initial breach she tossed One into seemed to have been a one-way accident and it closed behind him, with Eleven not fully aware of what she'd done. Likewise, the later portal was opened when Eleven's powers had gotten stronger, and Vecna implies during a later conversation that he'd been intentionally manipulating the Upside-Down to both invade through the portals and keep them open.

** The Orderly is revealed to be 001, formerly known as Henry Creel, and later Vecna.
** Eleven is revealed not to be the cause of the massacre of the rest of Brenner's test children, 001 is.
** The Upside Down is not just a parallel plane of Hawkins, it's specifically a Hawkins frozen on November 6th, 1983, the day that its interdimensional gate between the two planes was first opened.

* TearsOfBlood: This episode [[OnceMoreWithClarity clarifies]] that Eleven's tears of blood at the lab shown in an [[Recap/StrangerThingsS4E1ChapterOneTheHellfireClub earlier flashback]] were caused by 001 trying to psychically pull out her eyes from the sockets as he did will all the other victims.

* WeCanRuleTogether: When 001 offers Eleven the chance for them to dominate the world together, she refuses.
* WhamEpisode: The origins of both Vecna and Dr. Brenner's experiments, along with the truth behind the lab massacre, are revealed: Vecna was originally Henry Creel, the telekinetic son of Victor Creel who used his powers to kill his mother and sister (then framed Victor for the murders). He was later taken in by Dr. Brenner and became the first child (labeled "001") in the Hawkins Lab program, eventually growing up to become the orderly that "assisted" Eleven. After regaining his powers, 001 slaughtered the rest of the children and orderlies, but a telekinetic fight with El sent him tumbling into the Upside Down, where the dimension's lightning transformed him into the terrifying monster he is now.

** The final shot, where we zoom in on Vecna's wrist to confirm what had been implied: he is 001/Henry Creel/the orderly.

* {{Retcon}}: The flashbacks to the massacre reveal that Eleven first opened a gateway to the Upside Down not during one of Brenner's experiments, but when trying to kill 001.

* ExtraLongEpisode: At 98 minutes, it's the longest episode of the series so far.

* CreepyBasement: When Eleven enters the poorly-lid boiler room and has a JumpScare encounter with the orderly she was supposed to meet there.

* AmbiguousSituation: In order to get Eleven to agree with his plan, Henry convinces her that a) Two and the others plan to kill her as soon as he recovers and b) Brenner is perfectly aware of it and in fact ''planned'' for it to happen. While none of this is too out-of-character for the involved, the fact that it's [[ManipulativeBastard Henry]] [[UnreliableExpositor talking]] cast some doubt on the matter (for instance, Henry claims that Brenner deliberately allowed Two and his cronies to sneak out of their rooms and turned off the security cameras, but Henry could have done it himself, or the kids might in fact just have lucked out). We'll probably never know what would really happen if El didn't agree to escape.

* WhatAnIdiot: Brenner tells the other kids about Eleven's concussion from when Two and his lackies beat her up, and wants to know who was responsible for it since Eleven was keeping quiet. Two, for some reason, thinks it's a smart idea to say she probably just fell because she's "clumsy and stupid". Of course, Brenner immediately deduces that Two is responsible, and brutally punishes him for it.

* FromDressToDressing: Nancy rips parts of her dress off to make a bandage for Steve.

* CallBack: When Nancy admits to owning guns, Steve fondly reminisces about Nancy nearly shooting him with one of them.

* CrazyPrepared: Nancy admits to not only having guns in her bedroom, but also hiding them so they’re out of 6 year old Holly’s reach.

* HopeSpot: As Nancy climbs through the gate in the Munsons’ trailer, she doesn’t fall into the real world but instead into the pool at Steve’s house in the Upside Down. Cut back to Steve, and it’s revealed that Vecna has used Barb’s death to place Nancy under his thrall.

* CallBack: One's head cock as he [[spoiler: breaks the orderlies' necks]] repeats Eleven's exact gesture from Season One.