Qurac: The Team pass through Qurac itself to enter Bialya, a Qurac-type rogue state, in "Bereft". A map in the episode shows Bialya in the same location as Real Life Saudi Arabia, but another map in "Image" Quraq and Bialya are positioned similar to Iraq and Iran (based on the position of the Caspian and Black Seas on the map) and Batman mentions "baseless" claims that they used to be one country (Iraq used to be a core part of the Iran-based Persian empire).
Rabble Rouser: Sportsmaster does this to a crowd of adults after Klarion used a spell in "Misplaced" to send all the children to another dimension. This was done in order to allow the Riddler to sneak in undetected into STAR Labs property as the police were busy trying to quell the crowd from rioting.
In the original comics, both Artemis Crock and her mother Paula are white. In the TV series, Paula is portrayed as Vietnamese, while Artemis is biracial.
Like in Smallville, the Martian Manhunter's "John Jones" identity is African-American.
Rage Against the Mentor: Speedy is so outraged that the League (and by extension, Green Arrow) does not take him seriously that he essentially Ragequits. The rest of the boys threaten to do the same later, which convinces the League to make the group official.
Rage Against the Reflection: In "The Fix", Tigress (Artemis) smashes the mirror when she looks into it and sees her real face staring back at her, rather than the illusion everyone else sees, as she is so angry at the lie she is living.
Red Herring Mole: Though suspicion falls on several members of the Team, Artemis was the focus of suspicion in multiple episodes and actually assisted (Or at least stopped inhibiting) the actions of villains. Of course, the actual mole was covered in a completely separate reveal.
Reed Richards Is Useless: There are exactly two instances where someone uses their technology and abilities for something other than superheroics / supervillainy. First is Wally running a heart across the US for a transplant (a possibility which is never entertained ever again) and the second is the Reach sharing some of their tech with Earth, though in that case it was just to soften them up for invasion.
Averted a little by Lex Luthor (of all people) who uses advanced cybernetics to give Arsenal back his arm (and trip out out with weapons) and implies that lesser versions of this tech (the arm, not the weapons) are available. Also the world seems to function on a slightly more advanced tech than we have.
M'gann: What?....oh, yes, I can do that. I can still do that...
La Résistance: Dubbilex the DNAlien and an undisclosed number of the other Genomorphs were well aware that Project Cadmus was using them for purposes they felt were wrong, such as brainwashing the Guardian and Superboy, so they had been surreptitiously trying to get the Justice League's attention and aiding the young heroes all along.
Ret Canon: In DC Comics' rebooted "New 52" continuity, Artemis is reintroduced in Teen Titans Annual #1 (volume 4), resembling her Young Justice incarnation more than her original comic version. However, she's killed off (or at least put out of commission) in that same issue.
Retool: The second season was titled Young Justice: Invasion and opened with a five year Time Skip from the end of the first season. Quite a few members of the old group have joined the Justice League or moved on, many new teenage heroes have joined the Team, and some characters have changed identities. The format of the show moves away from switching between action and light-hearted character interaction and focuses more on just action.
Revenge: The faked death of Artemis has resulted in a slew of this. In no particular order:
The team wants revenge on Kaldur for killing her, aside from the ones that know better, obviously. Miss Martian actually went through with it by Mind Rape, to her own horror.
Cheshire wants revenge on Kaldur for the same.
Sportsmaster wants revenge on Black Manta because he considers it an insult that Kaldur killed her without Black Manta running by him first.
And finally Black Manta wants revenge on Miss Martian for successfully getting revenge on Kaldur by mind raping him. He is especially upset because Kaldur wasn't even given a dignified death, but instead turned into a vegetable incapable of earning one.
Rewatch Bonus: In 'Failsafe'; the team seems oddly casual after watching the entire Justice League disintegrated by attacking aliens. Then we learn that it was all just a training exercise, and they were aware of this at the start. Only after Miss Martian accidentally erases their memories do they begin to take it seriously.
Robotic Reveal: In the third episode, Mister Twister is revealed to be piloted by Bromwell Stikk. Except that Bromwell Stikk is a robot controlled by the real one. Later on, T.O. Morrow turns out to be a robot, too. The flesh-and-blood Morrow is a sickly old man on his deathbed.
The first thing Queen Perdita of Vlatava does after life-threatening heart surgery is tell her supervillain uncle she's revoking his title and diplomatic immunity. That is one tough kid.
Her uncle is a villainous example, actively working as the leader of the Injustice League and agent of the Light prior to his arrest. And speaking of which, two members of the Light are royal: Queen Bee and Ocean-Master/Prince Orm.
Martian Manhunter, despite being an alien, is almost identical to humans aside from his green skin, pupil-less red eyes, and ridged eyebrows. His niece Miss Martian ditches the pupil-less eyes and eyebrow ridges, essentially resembling a green-skinned human. the Martians' real form is actually huge, hunched and almost bat-like in shape. However, even Manhunter might be disguising himself once we get a good look at Green Beetle's natural form in Intervention.
Save Sat: After numerous alien incursions using zeta beam technology in Invasion, the Justice League sets up a series of satellites using technology provided by Adam Strange that prevents teleportation on to Earth from other worlds.
Save the Villain: Superman tries this with the Kroleteans about to be destroyed by a bomb hidden in their volcano base. They don't believe him and keep attacking, so he fails.
Scenery Gorn: A mental projection of Atlantis in "The Fix" is shown shattered into hundreds of pieces, reflecting the chaos of Kaldur's mind after M'Gann got through with him.
Screw This, I'm Outta Here!: Speedy quits being an apprentice to Green Arrow, and refuses to join the new team, because he feels insulted and slighted that the Justice League does not already consider him their equal. He views all subsequent attempts to get him to return to either position as the adults disrespecting, minimizing and attempting to control him.
Secret Identity Identity: Miss Martian wants everyone to know her through her shapeshifted "Megan" identity. Mostly this is to get away from the White vs. Green Martian classism on her home planet, especially since she's really a White Martian who works closely with the green Martian Manhunter.
Red Arrow and Cheshire also clearly developed one during the Time Skip, to the point of marriage and a kid.
Secret Test of Character: Black Manta has ordered an attempt to destroy a communications system that will set up contact between Earth and Mars. Kaldur, who is attacking the satellite launch, does not know that Black Manta has already smuggled a bomb on the rocket. When Kaldur fails to do the job himself and it goes up in flames anyway, he honestly attributes his success to a fluke. Black Manta wanted to see if he would take credit for a success that was not his own, since failure is a better judge of character than success.
Self-Fulfilling Prophecy: Impulse tells Jaime that he will become the vanguard of the Reach invasion in the future. Jaime freaks out and wants the Scarab off his back to prevent this. This leads him to trust Green Beetle, who fixes the Scarab and sets Jaime on the path to fulfilling that future.
Played with, however, Impulse's actions ultimately - albeit indirectly - ended with Jaime being free and the prophecy being destroyed. If Impulse hadn't shown up, Jaime would have eventually fallen to the Reach anyway.
Sequel Hook: At the end of "End Game," when things seem just about wrapped up, we see Warworld drift into Apokalips' orbit. Then, on the planet's surface, a Boom Tube opens up to the edge of a Fire-Pit, and Vandal Savage steps out to join Desaad. G. Gordon Godfrey, and a mysterious fourth figure. Then the figure turns around to reveal Darkseid, who shakes Savage's hand. "Business as usual."
Set Right What Once Went Wrong: Impulse travels back in time forty years to prevent a worldwide disaster, which was caused by a (now former) villain named Neutron. With the reformed villain's help, he is able to cure Neutron before he can do any lasting damage, but the future is still a wasteland regardless.
Sexy Shirt Switch: Of the "before anything happens" variety. In "Salvage", Artemis is walking around wearing only a shirt while talking to Wally.
Shapeshifting Squick: In the opening of "Images", Megan takes on Black Canary's form during a training session with Connor for a little roleplaying. Black Canary gently but firmly makes Megan understand that what she did was highly inappropriate.
Possibly why the latest group of superpowered teens is called the "runaways", including an episode title. They were more properly alien abductees and only ran away from League supervision.
Possibly unintentional, but the season finale of a two season super hero show involves the Heroes Unlimited cast coming together to break into teams and disable alien doomsday machines affecting the weather. Where have I seen that before?
Wally's Halloween costume in "Secrets" has the same letterman's jacket and pattern of hair as Teen Wolf.
In "Secrets", Miss Martian's "Martian" form is a slightly distorted Marvin the Martian with Godzilla's roar. The prankster that she is counter-pranking is even named Marvin.
When Miss Martian finds out that Billy is Captain Marvel, Kid Flash remarks "Yeah, and I'm Speedy Gonzalez."
In "Disordered", Superboy pilots the Super Robot Infinity-Man by docking his Super-Cycle on its head, just like how Kouji Kabuto pilots Mazinger Z with the Hover Pilder, or more directly how Tetsuya Tsurugi pilots the prototype Energer Z with a motorcycle-type Pilder in Shin Mazinger. (The feature isn't in the Jack Kirby comics where Infinity-Man first appeared.)
In "Schooled", Miss Martian briefly uses her shapeshifting powers to become a four-armed green-skinned Martian, reminiscent in form (though not in dress) of John Carter of Mars.
Also in that episode are Superman and Batman having a conversation in a diner. But unlike in How It Should Have Ended, they're in their civilian identities, and they're on the opposite of their normal sides.
In "Secrets", the magical sword of Beowulf (made up for the show) is sheathed in Grendel's arm, which Beowulf famously tore off.
In "Earthlings", Adam Strange quotes Lewis Carroll in order to get some Rannian policemen to chase him, specifically "Jabberwocky" and Alice in Wonderland. Later Alanna, who obviously has never heard this tale and does not speak English, tries to do this to Kroleteans:
In "True Colors", the Justice League logo that appears on Godfrey's show is identical to the logo for the DCAU series. Also the Green Beetle's name is B'arzz O'oomm, which when spoken sounds like Barsoom, the name for Mars in Edgar Rice Burroughs' John Carter of Mars series.
In "Agendas", Lex Luthor's high-frequency message to Superboy is the same tactic used by Gene Hackman's Luthor in 1978's Superman: the Movie, right down to the comment that with Superman off-planet (aboard the Watchtower satellite), "only one thing alive with less than four legs can hear this frequency"
There is a Saved by the Bell-esque show called "Hello Megan" that M'gann got her catchphrase from. It becomes a semi-significant plot-point later as the actress who played "Megan" makes an appearance and the revelation that Superboy's name, Conner, comes from that show. Has its own fabricated page now. Clips, including the opening sequence, are seen in "Image."
In the 4th Episode "Drop Zone" when Kid Flash and Robin are discussing chemical formulas, models of them appear on screen. They are the general representations of a steroid and a DNA purine.
The maps and locations given in the show are accurate to North East geography. Though why Batman thought Patterson, New York (population 11,306), was important enough to include on the map is a mystery.
In "Homefront" Robin asks Kid Flash to give instructions for constructing an EMP device. The components Kid Flash mentions are actual electrical devices and can be used in the construction of such a device. The Vircator is a vacuum tube that can generate pulses of either X-rays or EMPs, hence it being located in an x-ray machine, and Kid Flash's reference about it being a "stone" with a ten to the twelfth wattage is actually an accurate power level.
"Humanity" features a villain attempting to activate the Yellowstone supervolcano, a real-world doomsday scenario. The volcano itself, however, is completely wrong.
The episode "Coldhearted" has Wally carrying a heart for a transplant from Boston to Seattle at a dialogue-established speed of about Mach 1 (Wally's top speed at this point on the show). The amount of time it actually takes him is pretty close to how long it would take to actually make that run at that speed.
They also say that the heart would only be viable for 4 hours.
In "The Fix", all the additives listed as being in the Reach drink are real neurotransmitters, which would cause addiction over extended consumption. Admittedly, they probably wouldn't take the form of pink crystals.
Sidekick: It is not quite a Berserk Button, but Speedy in particular and the others do not really like being referred to as such.
Sidekick Graduations Stick: As of the beginning of season two, Dick Grayson has become Nightwing while Zatanna and Rocket have officially joined the Justice League alongside their former mentors.
Sincerity Mode: There's a moment in "Insecurity" where Wally drops the jokes and snark to honestly tell Artemis that she belongs on the Team and she shouldn't be worried about Red Arrow replacing her.
Sliding Scale of Plot Versus Characters: The show tries very hard to make this work, particularly by giving some characters "focus episodes". However, the story is so grand, complex and mysterious that it overshadows most of the characters present.
The entire team pairs off for this in the season 1 finale.
Played With in "War". When Mal and Karen get over their issues and kiss, Arsenal (just walking in) snarks about getting that as a reward. Wonder Girl gives him a peck on the cheek, which he considers "a start".
The Smurfette Principle: Until the very end of the premiere of there are no females, and for several episodes thereafter there's only Miss Martian. Even when Artemis joined up, there was still a pretty noticeable disparity for the bulk of the first season.
Averted as of "Usual Suspects". As of the first season finale, the team had an even split of four boys and four girls.
And then in season two, the new line-up consists of five boys and four girls.
The Reds have Red Inferno, an android programmed to believe she was a human female.
The Injustice League had Poison Ivy.
The Forever People have Dreamer.
Intergang has Whisper.
The Light has only one female member, Queen Bee.
The Runaways who received powers from the Reach have one female member: Asami. Being that they're all parallels to the ethnic Super Friends, which had no females, she's a genderflipped version of Samurai. As a nod to this, the three boys nicknamed her "Sam."
In "Performance," Robin and other members of the Team go undercover at Haly's Circus, where Dick Grayson performed with his parents as the Flying Graysons Trapeze Artists before his parents were murdered and he went to live with Bruce Wayne. Despite identifying himself as "Dan Danger," Jack Haly recognizes and calls him Dick, commenting that he has grown, but that there is simply no way to disguise a Grayson on the trapeze, and asks him for one final performance.
Mal says this to Karen after she proves instrumental in stopping the WarWorld in "War".
Billy Batson convinces Kid Flash that he's Captain Marvel by recalling Kid Flash's request for nachos after he had broken his arm.
In "Auld Acquaintance", Red Arrow is in hiding at one of his equipment caches, hiding from the mind-controlled Justice League, when Aqualad finds him. Just to make sure that he can trust Aqualad, Arrow asks Aqualad "Who broke your heart?" Aqualad answers with Tula... and Red Arrow himself, one of Aqualad's best friends, who was aiming an arrow at his chest the whole time.
When the Forever People are explaining who Desaad works for to Superboy, they refuse to speak Darkseid's name. Amusingly, Dreamer's projection of Desaad is the one that says "unspeakable", as if it has a mind of its own for that particular moment.
Red Tornado: Mission assignments are The Batman's responsibility.
Wally: Yeah, well "The Batman" is with "The Robin" doing the Dynamic Duo thing in Gotham.
Spanner in the Works: Even though the Light has a lot of contingency plans and generally manages to keep their gambit running, the Team has a very good track record of foiling their primary plans. It's safe to say they'd be in a much better position if not for the Team.
Speaks Fluent Animal: Captain Marvel seems to have the ability to communicate with animals, as he has an entire conversation with a tiger that he dubs "Mr. Tawny" in "Alpha Male;" in the comics, Tawky Tawny is a tiger companion of Captain Marvel capable of human speech.
Spiritual Antithesis: The show has this kind of odd symbiotic relationship with Teen Titans. The generally serious (though not without its moments of lightness) Teen Titans book was adapted into a zany Lighter and Softer cartoon (though not without its moments of darkness). The generally zany (though not without its moments of darkness) Young Justice book was adapted into a serious Darker and Edgier (though not without its moments of lightness) cartoon.
Spoiler Opening: Miss Martian and Artemis appear in the opening credits of every episode. Miss Martian does not actually appear until the very end of the pilot (putting her in the second episode when it was split into two parts for the show's regular time slot) and Artemis does not appear until several episodes into the show's run. Also, scenes from that particular episode will flicker briefly right before the Team Shot.
Spotlight-Stealing Squad: Season 1 was actually pretty good about balancing the spotlight and character development between the 6 (later 7) primary characters. Season 2, on the other hand, has been dominated by Miss Martian and Blue Beetle. Just to compare, the current Robin is much less prominent now than the original Robin was in season 1, while he still gets plenty of screentime while other Season 1 members have been Demoted to Extra.
Black Manta proves Dangerously Genre Savvy when he notices that Aqualad forgot to conceal his water-bearers when he and Garth stole the uniforms of two of his men.
When the Justice League was mind-controlled by Vandal Savage, one of the things that alerted the Team was Batmancalling them "kids".
Squishy Wizard: Zatanna is the only member of the Team who never does hand-to-hand combat.
Staged Shooting: Done in "Summit". Miss Martian (disguised as Deathstroke) 'shoots' Aqualad and Artemis as part of a plan to extract an Engineered Public Confession out of the Reach and the Light. The 'deaths' are then revealed as special effects.
Robin appears to have inherited Batman's tendency for this, and the other members of the Team find it extremely frustrating.
Kid Flash: "I forgot how much I hate it when he does the ninja thing."
In "Downtime", Aqualad demonstrates to Garth that he seems to have picked up on this trait from Robin.
Villains in general are very good at disappearing quickly when visibility is impaired.
The master of this trope, Batman himself, manages to pull it off twice in one fight. Against Robin.
In season 2, when Black Manta II fires a small missile at Aquaman, Lagoon Boy, Superboy, Superman and Nightwing. When the smoke clears, he, Superboy, and Nightwing have all vanished, and Nightwing actually beat him to his getaway route.
In "Revalation" when Aqualad tells Robin and Miss Martian to do recon, they have already disappeared. He doesn't notice however.
In "Beneath", Wonder Girl, Batgirl, Bumblebee and Miss Martian are hanging out on a dune. Wonder Girl looks away for a second, and when she looks back, all three are gone.
In that same episode, Batgirl does this to Bumblebee.
Tim Drake may have pulled off the most skilled one in "True Colors," when he manages to steal some of the Reach's additives while they're close enough to hear him breathe.
Stealth Pun: In his first scene in the pilot, Wally gets given the "cold shoulder" by Captain Cold.
Even better, the entire first five minutes of the pilot features four ice villains, and is thus one gigantic "cold open". (Involving Batman)
Stepford Smiler: In a deviation from his comic book counterpart, it's revealed that Impulse's Fun Personified personality is essentially a facade designed to hide the true details of his mission to the past.
Stock Scream: Not even Young Justice is safe from Wilhelm! For the curious, it occurs in "Drop Zone", when Superboy tosses Mammoth into the Kobra thugs.
The commercial for Reach's new line of energy drink.
Suicide Mission: "Failsafe" ends with an invasion of the alien mothership that Superboy, at least, knows is going to be a one-way trip. Robin and Kid Flash, though they had hoped to survive, were trapped within the ship and caught in the explosion.
The Summation: Occurs at the end of "Depths," where the audience is shown in detail how Aqualad and Nightwing helped Artemis fake her death.
The sixteen-member Justice League has Hawkman and Hawkwoman, and two Green Lanterns, Hal Jordan and John Stewart—with Guy Gardner also on Earth and willing to pick up any slack.
Defied by the Team itself; though they accept Artemis into the group, Kaldur points out that they do not have "a quota on archers" and that Roy is still free to join whenever he wants. Even moreso in season two, where the Team expands its roster and has Batgirl, Robin, and Nightwing (Badass Normal with gadgets), as well as Wonder Girl and Superboy (Bricks, Flying and Not Quite Flying respectively.)
Super Human Trafficking: The Light have been sending metahuman teenagers to their mysterious alien partners for some unspecified reason.
Superhuman Transfusion: In "Images", Garfield Logan gained shapeshifting powers after receiving a blood transfusion from Miss Martian.
Superman Stays out of Gotham: Averted. "Schooled" opens with a Metropolis bridge collapsing. Superman runs in, Batman prepares to lend a hand, and Superboy shows up to help. During Superboy and Superman's conversation, Superman gets a call from Green Arrow and rushes off. Team-ups are common, everyone fights each other'sRogues Gallery members, and the League functions as an international organization. The entire reason the Light exists is in direct response to the aversion of this trope.
Superpowered Evil Side: How they are playing Blue Beetle's relationship with the Scarab; it is not actually any more powerful than when Jaime is in control, but more willing to use Beetle's more dangerous weapons, and is more skilled.
Superpowered Mooks: The Kobra-Venom infused animals controlled by the Brain in "Alpha Male". Fortunately, destroying their inhibitor collars releases them from the Brain's mind control and renders them neutral.
The Venom-Blockbuster formula known as Kobra-Venom.
Superboy is given a sort of Superer Serum in "Agendas". His human father, Lex Luthor, gives him a pack of "Shields", slap-on patches that suppress his human DNA, allowing him to use flight, heat-vision, and his full Kryptonian speed and strength for about an hour.
Super Strength: Superboy is the strongest member of the team, but Aqualad and Miss Martian also have strength beyond that of a normal human.
Sure, Let's Go with That: When Superboy needs a civilian last name, Martian Manhunter suggests Kent. Not being privy to Superman's secret identity, Miss Martian and Superboy assume that he's referring to the late Kent Nelson, who they've met.
Taking You with Me: In the climax of "Revelation," The Joker attempts to release his Joker venom and kill the Injustice League and the Justice League en masse after the Justice League arrives to apprehend him and the rest of the villains.
Tank Goodness: The Bialyain army uses tanks effectively against the Team in "Bereft".
Inverted with Aqualad, who has very large and noticeable tattoos on both arms but is one of the good guys. At first
Played straight with Devastation, who is covered in thorn tattoos.
Taught by Experience: All the original members of the Team have done this to some extent or another during the Time Skip between the seasons. They have gained not just combat skill, but maturity and intelligence as well, and are now trying to pass that wisdom on to the next batch of teen heroes.
Zeta-beam tubes are commonly used by the title team and the League. They make it possible for Aqualad, Kid Flash, Artemis, and Robin to live outside the hideout at their individual homes in Atlantis (it's a country in this universe, not a city according to Word Of God), Central City, and Gotham respectively.
A "Boom Tube," the preferred means of transportation for the New Gods, appears in "Bereft" and "Disordered".
Tempting Fate: Artemis asks Wally what is the worst that could happen with her temporarily coming out of retirement to go on a dangerous mission. The very next scene is her death. It is later revealed that her death was staged and she is about to go under cover, where she again asks what is the worst that could happen.
Wall does it himself in "Summit." Naturally, by the end of "Endgame," he is dead.
That's No Moon!: In "War", this is Nightwing's reaction when he realizes that the WarWorld is actually far larger than the moon it is passing by at the moment.
That Thing Is Not My Child!: Superman is understandably hesitant to accept Batman's description of of him as Superboy's father. Who wouldn't be when saddled with a teenaged son they've never met who is essentially the product of their rape.
After "Failsafe" the Team members get a much needed therapy session with Black Canary, though she isn't an accredited therapist.
In "Terrors", Miss Martian and Superboy attend therapy while disguised as the Terror Twins. Miss Martian uses it as a chance to try and get Superboy to deal with his issues with Superman, but considering the nature of the inmates in that prison, the doctors on staff aren't terribly good at their jobs.
However, this is seemingly played straight with Arsenal, who doesn't seem to have received any psychological counseling or therapy after being mutilated and losing eight years of his life in a cryogenic tube, to the point that he tried to kill himself rather than let himself be captured by Blue Beetle. However, it may just be that he is refusing to see one.
There Was a Door: In "Misplaced" Billy scales a 10 foot chain fence to enter an airport, despite the fact a wide open gate is situated only twenty feet further down the fence.
They Knew the Risks: Nightwing's defense when Kaldur blames him for getting Aquagirl killed during a mission.
Time Skip: Five years (and sixteen hours) between the first season and the second. Note that the Batman Cold Open of the second season's first episode is set up to fool the viewer into thinking it continues directly from the previous episode.
Title In: Locations are introduced in this way and so are the dates.
Tomato in the Mirror: Red Arrow was the most gung-ho about finding the mole, only to find out that he was unknowningly the mole the entire time. Even worse, he is actually a clone of the original Roy Harper, who was kidnapped by the Light three years prior.
Top-Heavy Guy: Tommy of the Terror Twins has a huge muscular upper body after the Time Skip, but his legs have relatively a lot less muscle.
Trailers Always Spoil: The commercial still during the debut spoiled that Miss Martian and Artemis would join the Team.
The starting theme also featured Artemis in the episodes before her introduction.
Training from Hell: The scenario from "Failsafe" was an unintended example on the part of the Justice League, when Miss Martian began to believe it was real and that belief overrode the rest of the Team's conscious knowledge it was fake.
Translation Convention: The Atlanteans in "Downtime". At first everyone is speaking Atlantean with subtitles, but start speaking english after a minor character casts a spell. Word Of God says that it was a translation spell.
Blue Beetle's scarab armor can translate the Krolotean language for Beetle, and can even automatically translate Beetle's English (With occasional Spanish) into the Krolotean language. To everybody else present it is unintelligible gibberish.
In "Earthlings," it is revealed that Miss Martian can function as a translator if she is able to set up a psychic link between multiple parties. Each still speaks his or her own language, but everybody else hears the words in their own tongue. Superboy specifies that it is subconscious on her part once she sets up the initial link, so she cannot "hear" what you are saying if you are out of earshot.
Lex Luthor can temporarily neutralize Superboy with the words "Red Sun".
Red Arrow can be put into a pliant state with the words "Broken Arrow".
Troubled Fetal Position: Artemis, towards the end of "Homefront," when facing the prospects of every friend she has dying and her being unable to do anything about it.
True Companions: Artemis says this to Cheshire's mask in "Homefront," calling the Team her real family.
Truncated Theme Tune: Young Justice season 1 returned from its last hiatus with the theme song reduced to a five second bit of the tune and its title card, rather than the 20 second one that introduced all characters. This was at least partly to make room for the DC Nation shorts that appear before/during/after the show. Foreign broadcasts keep the extended theme song.
Truth-Telling Session: "Usual Suspects". It's set up to look like Connor, M'Gann and Artemis are ALL selling the Team out for different reasons... and then a three-stage flashback shows them opening up about their issues one-by-one.
Wally: So, uh, who's next?
M'gann: I am.
Wally: I swear I was kidding!
Turn Out Like His Father: Zigzagged with Batman and Robin I/Nightwing. Dick initially wants nothing more than to be Batman's successor and this is what everyone expects, given that the other Leaguers started taking sidekicks mainly because they thought Batman was right to ensure that someone would be able to carry on his work. However, Dick later comes to the conclusion that he doesn't enjoy being the sort of obsessive person who will sacrifice everything to win, and Bruce reveals that he never intended to train Dick as a successor— all he wanted was to give Dick a chance to catch the man who murdered his family and keep from being that same kind of obsessive person. Five years later, however, Dick has further concluded that while he isn't the kind of fanatic Batman is and doesn't want to be, that doesn't change the fact that he's good at it.
Twincest: Sort of. Superboy and Miss Martian start making out while undercover as the Terror Twins in "Terrors". Icicle Jr. isn't too pleased.
Twin Telepathy: Superboy and Miss Martian pretended to have this while undercover in "Terrors".
Two Beings, One Body: Intergang uses an Apokoliptian device to merge four dead Appellaxian host bodies (large, Golem-like creatures formerly animated by energy beings) into one living one.
Two Girls to a Team: Artemis and Miss Martian. This trope was so enforced in the minds of its demographic that rumours that another female team member (either Wonder Girl or Secret) would be joining the cast launched much speculation that either Artemis or Miss Martian would be outed as The Mole, die, or otherwise leave the team.
This trope, and the anxiety associated with it, has been averted with the inclusion of Zatanna as a long term member without any other character being removed from the team. As for the series’ other big team, the Justice League, although there are three female members on the team, which technically means it doesn't count, the full roster is sixteen members so the essential truth of this trope is still in play. Interestingly, Wonder Woman seems to be actively working against this, as one of her stated criteria for an ideal new member to the League is that they be a woman to help shift the gender ratio.
As of the end of season 1 Rocket and Zatanna have joined the Team, so that the gender ratio is even with four boys and four girls.
As of season 2, the ratio for the team stands at five males and four females.
Two Lines, No Waiting: Many episodes alternate between two plots, one with more action, and one with more character moments.
Underestimating Badassery: The Riddler is the laughingstock of Belle Reve penitentiary, excluded even from eating lunch at the same table as the other prisoners, but is the only prisoner to manage to escape at the end of "Terrors."
Unwitting Pawn: Lex Luthor lies about being one to the Reach to get the Runaways on his side. Later dialogue from Queen Bee implies that it's the other way around.
Utility Belt: You are aware this universe has Batman in it, right?
Verbal Tic: Robin's tendency to ponder words and their prefixes ("whelmed", for example) and giggling when he joins battle. Episode 5 shows that he actually puts in a lot of thought to it, and that the rest of the Team is picking up on it and using it.
Vichy Earth: The eventual goal of the Reach. In Impulse's time, they've successfully turn Earth into a planet of slaves.
Villainous Breakdown: Klarion has it after he gets beaten the first time, Vertigo has one when Flash tricks him into confessing to attempted regicide, the Reach Ambassador has one between War and Summit, Black Beetle has one after Blue Beetle turns the tables on him, and Vandal Savage has one after the team not only shatters his alliance with the reach, but expose him as the true mastermind of the rimbor attack 6 ago, forcing him to flee the earth.
Visible Invisibility: Both Miss Martian and her bioship have the ability to stealth themselves by bending light around them. It is not true invisibility though and either one can be detected if moving around too much or the observer is particularly...observant.
Vocal Evolution: Quite prominently in Jesse McCartney's Nightwing. While his Nightwing voice in the the first four episodes of the second season was deeper than his Robin voice, it still didn't sound like a guy in his late teens (Dick, as Nightwing is about 18-19 years old). His voice deepened slightly in the second season's fifth episode, and this got particularly noticeable in the sixth episode of Invasion.
Wake Up, Go to School, Save the World: The creators say that the Team will be dealing with normal adolescent obstacles such as romantic struggles and of course school, in addition to being a superhero team.
Walk-In Chime-In: Happens a few times, usually when someone enters the room via boom tube or flies into a conversation. Robin is frequently guilty.
Walking Shirtless Scene: Superboy's shirt usually ends up ripped in whatever episode he's in, when he bothers to wear one at all.
Jaime seems to be fulfilling this role in Season 2.
Superboy wants to learn from Superman, but Supes distanced himself from the kid until the New Year's episode.
Bruce Wayne: That boy needs his father. Clark Kent: (angrily) I am not his father!
Robin shows some signs of this as well, being visibly jealous when Batman asks to speak to "Just Aqualad" after a failed training mission. Fortunately, Batman is fairly Genre Savvy, and as soon as he notices Robin's hurt feelings he invites him outside for a father-son basketball game. He refers to it as "training" but his real intentions are obvious.
Icicle, Jr. wants to earn the respect of his father, Icicle, Sr., who is the dominant prisoner in Belle Reve.
In "Usual Suspects", it turns out that Red Arrow is The Mole via mind control, and he has not only allowed The Light access to the Watchtower, but has also infected the entire Justice League with mind-controlling nanotechnology.
"Before The Dawn" has M'Gann finding out about Aqualad being a Fake Defector, but only after putting him through Mind Rape, Blue Beetle discovering he is the key to a Reach-created apocalypse and the Reach making agreements with the United Nations and gaining public favor. We also find out that the Reach are trying to weaponize the meta-gene in humans and have an army of ships ready, and the ships are probably not to help humans.
"Runaways" confirms that Green Beetle and Blue Beetle are actually under Reach control.
"Summit" starts out with some slow deliberations between the Light and the Reach and the recent problems in their partnership when suddenly R'as al Ghul pulls the magic necklace off Tigress's neck revealing her to be Artemis, immediately exposing Aqualad as a double agent, after which both of them are shot in the chest right then and there. But wait, Aqualad dropped a holographic projector right before he died that exposed the Light having manipulated the Reach from the very start, ruining their partnership and Savage confesses that they stole the Crystal Key. But wait, it turns out Aqualad and Artemis are actually alive and merely wanted the Light to confess to the theft and Deathstroke is actually Miss Martian in disguise and the rest of the team was just waiting in cover. But wait, the Light has cyber ninjas for backup. But wait, the cyber ninjas are actually the other half of the Team in disguise. But wait ... okay, you get the idea.
What Measure Is a Non-Human?: Miss Martian "kills" the robotic mannequin controlling Mister Twister. The others only complain because they did not know he was a robot, and once that is revealed they drop the subject.
Just a Machine: When they objected, she claims it's okay because it's "Just a robot", which leads to them dropping the subject.
Nabu to Kent Nelson for not putting his powers to their full use. Kent telling Nabu that he can't keep Kid Flash's body as his host.
Aqualad gets one from the rest of the Team in "Alpha Male" for not telling them there was a mole. They later apologize for overreacting and admit his reasons were justified.
In "Failsafe", Miss Martian gives one to Robin for sending Superboy on a suicide mission, saying that Aqualad wouldn't do that. Robin counters that Aqualad would sacrifice himself, which is why he's dead and they have no leader.
In "Agendas", Captain Marvel calls out Nabu for taking over Zatara's body in "Misplaced" and questions whether someone willing to do that belongs on the Justice League.
Kid Flash does this to Artemis in "Insecurity", when she seemingly misled the Team simply to prove herself better than Red Arrow, who had just agreed to join the Team.
Superboy looks like he is about to do this in "Earthlings" in regards to M'Gann's Mind Rape of the Kroletean leader, but she cuts him off before he can finish since there are more important things to focus on. He gets it out in "Depths."
Wally gives one to Nightwing in "Darkest" for letting the cave be destroyed and three other team members be captured. He then points out that it is entirely possible that Aqualad might really have turned, and if so then they are just playing into his hands.
In "Before the Dawn", Artemis gets to give one to M'gann for mind-raping Kaldur.
Superboy and Lagoon Boy lay into Nightwing for hiding the truth behind Kaldur's defection and Artemis's death in "The Fix".
The Runaways call out Nightwing for being kicking Arsenal off the team after he saved them, and take him with them.
What Would X Do?: Aqualad manages to get Superboy on his side in the pilot by asking "What Would Superman Do?"
Whole Plot Reference: The main plot of "Coldhearted" is taken directly from the comic book "The Flash Vol. 2 #1", the issue where Wally became The Flash for the first time after his career as Kid Flash.
Why Am I Ticking?: In "Satisfaction", Speedy wraps a length of detcord around Mercy's robotic arm while fighting her. She has just enough time to realise why he is looking smug before he presses the detonator.
Why Don't You Just Shoot Him?: When Desaad uses the Father Box to reprogram Infinity Man and make him attack Superboy, a mook asks why Infinity Man (obviously the superior combatant) doesn't just kill Superboy outright. Desaad explains that he is not one to end things so quickly, and the Father Box is designed to emulate his mindset.
Witch with a Capital B: In "True Colors", courtesy of Black Manta. M'gann's not a witch, but the intent is clear.
Black Manta: I will have my revenge on the Martian witch that did this to him.
The Justice League or some of its members being taken out often times happens.
Red Volcano briefly in Season 2. In his first appearance, he took on the entire team and was only neutralized by Red Torpedo and Red Inferno's Heroic Sacrifice. Here, Blue Beetle alone manages to take him down, to show just how dangerous the rebooted Scarab is.
Lampshaded in "The Hunt" when the Runaways fight Black Beetle and he takes down Tye first. Tye recovers though, and manages to get a few hits on Black when the Runaways Zerg Rush him.
Ed: Please tell me he did not just take out our big gun in three seconds flat.
The beetle drones in "Endgame" were supposed to be as strong as a Beetle warrior like Black Beetle. While they may have had similar weapons, someone apparently skimped on the armor, as it takes literally no effort for even Badass Normals to destroy them despite Black Beetle being able to solo the entire team.
Poor Wonder Girl never even got to be built up as powerful before her abrupt Worfing - her very first appearance has her get trashed by Lobo, and literally every onscreen fight she has had against a named enemy includes her snaring them with her lasso and them immediately using said lasso to smash her into the ground. One wonders why she uses the thing... and, for that matter, why the writers use her, if they won't let her do anything.
When Mammoth is introduced in "Drop-Zone", his first act is a Curb-Stomp Battle where he wipes the floor with Bane.
Worf Had the Flu: When fighting the mind-controlled Justice League, Artemis is amazed that they haven't been killed already. Wally points out that since the mind-control is more like remote-control, the League's actions have to be controlled by someone, Klarion. Klarion has to micro-manage every member, and this bottlenecks their performance to a threat that the Team can hope to survive.
The reason Despero did so much damage in "Cornered" was because Miss Martian was still suffering Heroic BSOD after mind zapping Kaldur.
Working with the Ex: After the Time Skip, Miss Martian and Lagoon Boy are now dating. Conner has voluntarily chosen to stay on the same team with M'gann, even though he has the option of joining the Justice League, but he is clearly uncomfortable with their relationship.
None of the villains so far have any qualms about attacking minors with lethal force. Mr. Twister commented on the fact that he was fighting children, and found the fact that the Justice League was using children to be disturbing, but he didn't hold back because of it.
In episode 18, "Secrets", Harm is revealed to have murdered his younger sister to obtain power and purity of heart.
In "Coldhearted", Count Vertigo plots to kill his own ten year old niece to take control of his country, as his niece is currently Queen, by withholding a heart transplant from her. Fortunately, Kid Flash stops his plot and Vertigo ends up humiliated in Belle Reve.
Written-In Absence: Robin does not appear in "Denial" because he is "doing the Dynamic Duo thing with the Batman in Gotham". Aqualad gets a similar excuse in "Image".
Wrong Genre Savvy: Blue Beetle uses a Chest Blaster to send Volcano flying while the runaways free themselves, even telling Volcano not to stereotype. This foreshadows the fact that Jaime isn't the one in control.
Xanatos Gambit: Every time The Team or the League defeat an Evil Plan, the Light manages some sort of victory and moves one step closer towards their endgame. This show is run by the man who created David Xanatos, after all.
X-Ray Sparks: The alien weapons in "Failsafe" cause anyone hit by them to light up, revealing their skeleton before disintegrating the victim.
You Can't Go Home Again: According to the treaty between the Reach and the Guardians of the Universe, Green Lanterns cannot enter planets that are under Reach control, which may cause problems for Hal Jordan, John Stewart, and Guy Gardner.
Also the case for Miss Martian, Superboy, Beast Boy, Lagoon Boy and Mal Duncan, who were all living in the Cave when it blew up.
Your Mind Makes It Real: In "Failsafe", Miss Martian accidentally hijacks the training simulation created by the Martian Manhunter, causing anyone who "dies" to slip into a coma in the real world. In "The Fix", while she and Artemis infiltrate Kaldur's shattered mind, she warns Artemis that the projections will only hurt her if she believes in them. Ironically, Artemis keeps her head and stays out of danger, while Miss Martian's guilt makes her vulnerable even though she should know better.