Laser Blade: Whisper wields a pair of laser whips against Superboy and the Forever People in "Disordered".
Laser-Guided Amnesia: Psimon erases the last six months of the Team's memory in "Bereft". This leaves Artemis and M'gann strangers to everybody else, Superboy completely mindless, and Robin, Kid Flash, and Aqualad ignorant of the current mission.
Aqualad is a calm, levelheaded one. He is replaced by Nightwing in Season 2, who is a bit more devious.
With the Runaways, the leader seems to be "whoever has a good plan at the moment". It mostly winds up being Virgil, who's has a penchant for making it up as he goes, but Arsenal and Tye have also led them at different points.
In "Terrors", during a therapy session at Belle Reve, Superboy snaps at Miss Martian that they "don't live in a fantasy world where all problems are solved in half an hour." In "Image", M'gann explains how she envies Megan from 'Hello Megan!', including the fact that all of her problems can be solved in twenty-two minutes.
In "Failsafe", before the Team heads off against the alien invaders.
Superboy: So what are we waiting for, a theme song?
In "Endgame", Superboy pretty much voiced the exact thoughts of the viewers after learning Robin & Wonder Girl have begun dating off-screen.
Kid Flash is guilty of this in the pilot. And also in "Drop Zone", where he shoots the Team's "stealth" orders to hell by rushing headlong into a crossfire between Bane and Kobra cultists.
Robin is the most frequent embodiment after the Team forms, and is one of the reasons that the leader position is eventually ceded to Aqualad.
In "Performance" Superboy does this in near perfect form before the final confrontation with Parasite. The one missing element is that he just screams instead of shouting his name.
La'gaan does this in "Depths" when rushing in to battle with Black Manta's soldiers. It doesn't end well for him.
In "True Colors" Alpha Squad (Arsenal, Impulse, Blue Beetle, and Robin III) run a covert mission on a farm owned by Lex Luthor, to which Robin hacks the computers to make it seem like everything is normal. Lex and his security believe it...until Arsenal sets off an explosion setting off an alarm and alerting Lex to their presence, forcing Alpha Squad to fight their way out.
Left Hanging: Due to being Screwed by the Network, the show ends with Wally dead, Virgil joining the team as Static, Artemis retiring her old name in favor of Tigress, Nightwing taking a leave of absence, Lex Luthor poised to run the UN, and Vandal Savage has taken the War World to Apokalips to see Darksied, who greets him as an equal. It essentially ended on a major reveal and some major shocks.
Blue Beetle, Jaime Reyes, after Ted Kord was killed by the Light during the Time Skip.
Mal Duncan becomes the new Guardian after Jim Harper retires.
Bart Allen becomes the new Kid Flash after Wally's death in the series finale.
Legacy Immortality: Jaime mentions that most of the general public thinks he is Ted Kord in a new costume. The real Ted was killed during the Time Skip, and Jaime laments that the world will never know of his sacrifice.
Let's You and Him Fight: In "Disordered", this looks like this will happen between Superboy and the Forever People... but then it's promptly subverted thanks to the intervention of the Forever People's Mother Box.
In "The Hunt," Arsenal sets Mongul up to fight Black Beetle so that the Team can make their escape while the two are distracted.
Lie to the Beholder: In season 2, Artemis infiltrates the Light using a magic necklace that hides her identity.
Light Is Not Good: The Big Bad of the series is actually called "The Light", and appeared for half the season simply as pure-white outlines. Glowing with unearthly radiance, no less!
Loads and Loads of Characters: Word of God says the complete list of characters will increase as each season passes. Current count as of episode 24, season 1: 174 supporting characters from DC Universe alone, according to Word of God. The second series, Young Justice: Invasion features even more new characters.
Lockdown: In "Terrors", Amanda Waller locks down Belle Reve in an attempt to stop the mass breakout.
Love Dodecahedron: Kid Flash likes Miss Martian and "hates" Artemis. Miss Martian likes Superboy and recommends to Artemis that she should ask Kid Flash out, but Artemis also likes Superboy. Superboy eventually returns M'gann's affections and they begin dating, but Wally and Artemis are still pouting themselves. It eventually all settles itself out at the end of season one.
Macross Missile Massacre: When Mongul's attempt to destroy Earth outright with a Wave Motion Gun fails, he turns the WarWorld's considerable stockpile of missiles on the planet. It takes all the space-capable assets of the League and the team, Earth's collective military might, and the entire Reach armada just to match the sheer number of missiles, and the Reach lost two-thirds of their armada doing it. Mongul wasn't going to run out of missiles, either, meaning he would have won by attrition.
Makeout Kids: Megan and Conner. Fortunately, they have a giant robo-sphere that can somehow discreetly warn them before anyone sees them.
Make Way For The New Villains: Three episodes into the second season, the villains up to that point, the Kroloteans, are wiped out by a bomb made by The Reach, The Light's new partner.
Malaproper: A German example. The spell Klarion and the sorcerers are chanting in "Misplaced" is actually "We are the whistlers of Hamelin" ("Wir sind die Pfeifer von Hameln"), instead of "We are the pipers of Hamelin" which would roughly be "Wir sind die Flötenspieler von Hameln" with "die Flötenspieler" literally meaning "the flute player". Also in actual German "the Pied Piper" was known as "the Rat Catcher" so to be more accurate with the language they should be saying "Wir sind die Rattenfänger von Hameln".
Male Gaze: Funny how at the beginning of "Infiltrator", Miss Martian's the only one to get a leering pan-up of her in her bathing suit.
Artemis Crock gets this in "Homefront" (with her embarrassingly short school girl uniform skirt) and "Salvage" (the latter taking place five years later, strutting her stuff in a football jersey - and nothing else).
Manchurian Agent: Red Arrow, a deep-cover operative planted three years before the show began, responding to phrases by his handler, Sportsmaster..
Tye has gone on a quest of awakening that will connect him to his heritage and show him the path to his destiny. note Tye's metagene is activated by the Reach and he gets superpowers.
*to Jaime* You search for answers, but the answers you seek will find you. note Jaime's been wondering about the Scarab, and Impulse arrives from the future and eventually answers his questions.
May Contain Evil: The Reach soft drink is designed to mutate human DNA over several generations, making humanity loyal to the Reach.
Meaningful Echo: In season 1's "Targets", Cheshire's first attempt to kill Lex Luthor is with a rocket launcher, but misses. In season 2's "Satisfaction", Speedy's first attempt to kill Luthor also involves a rocket launcher.
Meat Moss: The lower levels of the Cadmus lab has this look. It actually serves a function however, used to incubate their bio-weapons.
Men Are Generic, Women Are Special: Played with in "Beneath". Nightwing had a perfectly good strategic reason for sending an Amazon Brigade after Queen Bee, but Batgirl points out that he's never felt the need to justify sending an all-male squad on a mission. Nightwing says there's no right response to that and ends the transmission. To be fair, considering that Queen Bee is one of their top enemies in the Light and that she murdered the mother of one of their teammates, the girls probably already knew what her powerset was, and Batgirl actually says she was trolling Nightwing. The basic argument comes down to one side saying that Nightwing needs to shut up because he thinks an all-female squad is abnormal enough for him to be mansplaining his reasoning to Alpha Squad, and the other side saying Batgirl needs to shut up because Nightwing is absolutely right.
All of the kids have individual mentors in the heroes they are sidekicking to (Robin gets Batman, Kid Flash gets Flash, etc.). The Team as a whole has three mentors: Red Tornado, Black Canary and Batman.
In season two, Miss Martian, Superboy and Nightwing have turned down membership on the Justice League so that they can mentor the new members of the Team.
In "Images," M'gann leaves Psimon drooling and unresponsive after their psychic confrontation. He's better after the Time Skip.
In "Earthlings," Miss Martian probes the mind of the Krolotean commander to learn what the League did in their missing sixteen hours. During the probe the Krolotean begins to drool from the mouth. After it is done the Krolotean is comatose and carried off by his compatriots, never once even responding to them carrying him. In "Alienated", she does it again to another Krolotean... right in front of Batman and Martian Manhunter. "Depths" suggests it's become a recurring habit since season one and is the primary reason she and Superboy broke up. The final straw was her trying to wipe away Superboy's memories of the argument. He described it as a perversion of the mental bond with M'gann that he used to love.
"Before the Dawn": Miss Martian mind-rapes Kaldur'ahm for supposedly killing Artemis. When she discovers he never did, they both slump to the floor—Kaldur from the attack, M'gann from her own Heroic BSOD.
Mistaken Identity: In "Homefront", Artemis hears Red Tornado call out her and Robin's code names and assumes he has come to save them from the bad guys. It turns out to be Red Torpedo, who has the exact same voice as Red Tornado.
The Mole: The coda of "Infiltrator" indicates there is a mole within the Team, but his or her identity is not revealed. Suspicion falls on the newer less-known members of the group, Superboy, Miss Martian, and Artemis. It is revealed in "Usual Suspects" that Red Arrow was The Mole, and even he had no idea.
Mood Whiplash: From "War", after everyone celebrates for beating up Mongul and stopping the War-World, Blue Beetle knocks out Impulse with one strike, and pretty much disables the rest of his 'teammates', because the Reach have already taken complete hold of him.
Moral Dissonance / Moral Myopia: Wonder Woman shows shades of this during 'Agendas'. When it's brought up that Captain Marvel never told the League that he was 10 years old, she is visibly angry at him for 'lying' to them. However, it's been shown that the League are not required to reveal their identities to each other, and to do so is a sign of personal trust between members. Billy not telling Diana about his ID is no worse than Batman not telling Billy his secret ID. Likewise, she's visibly pissed at Batman for training Robin to be a crime fighter, yet Amazons are raised from birth to be badass warriors. So in short, if she and her friends keep secrets from you, or her people train their children to kick ass, that's fine. If you keep secrets from her and her friends, or train your children to kick ass, she's outraged.
Superman can seemingly show instant compassion to anyone and everyone regardless of who they are, where they come from and what they've done - unless that someone is Superboy. And the only way Superboy can get any kindness from Superman is to save his life.
Red Arrow acts like a Jerk Ass non-stop and is then surprised to find that 9 out of 10 people don't like him and/or don't respect him.
My Kung-Fu Is Stronger Than Yours: In "Misplaced", Zatanna tries to use a spell against Klarion, only for it to fizzle pointlessly against his shield. He dismisses her attempt as "baby magic", then uses her type of spellcasting to send her flying.
Mysterious Past: Artemis has a hidden history which is slowly explored over the first season. Red Arrow is aware that her story of being Green Arrow's niece is a lie, and her father would theoretically ask her to kill people. Her fear of the truth being discovered is a strong motivator, and she once let a villain escape after the threat of exposure.
The initial lineup of the Team, Robin, Aqualad and Kid Flash, was the lineup of the original Teen Titans.
Aqualad's real name Kaldur'ahm is a reference to Calvin "Cal" Durham, a former henchman of Black Manta turned ally to Aquaman. The tie-in comics include Durham as Aqualad's father. Season 2 of the show reveals Black Manta is his true father.
In "Schooled" Bruce Wayne flips back the head of a bust, revealing a button used to access his costume, which was the standard means of access in Batman.
The Justice League's Washington DC headquarters is the Hall of Justice from Super Friends.
Artemis is shown carrying a small collapsible crossbow as a backup weapon. In the comic books, the adult Artemis wields a crossbow as her primary weapon.
In "Denial", Kent Nelson meets a scam artist giving false psychic readings named Madame Xanadu, whom he even comments has the "right aura for the job." In the comics, Madame Xanadu is an actual psychic and powerful sorceress.
Another soldier is named David Reid, Magog's real name in the comics.
In the Halloween episode "Secrets":
Mal Duncan dresses like the 1990's comics Superboy, Karen is wearing an old version of the costume she wears in the comics as Bumblebee, and students dressed as Donna Troy and Harley Quinn can also be seen.
The episode title reflects that, in the DCU, Match wasn't created by Cadmus but by an Evil Counterpart called The Agenda.
Additionally, Luthor's trigger phrase to incapacitate Superboy is "Red Sun". Kryptonians gain superpowers from yellow sun energy, and red depowers them. This also refers to the comic Superman: Red Son, which features a Superman raised in Communist Russia who battles a morally grey Lex Luthor, but in the last panels Superman is revealed to have been Lex's descendant sent into the past by his parents.
Captain Marvel says "You thought I was a Kryptonian?" to Superman. Before they obtained the rights to Captain Marvel, DC sued the creators of the character, alleging that Captain Marvel was a copy of Superman.
The reporter Artemis and Green Arrow save is Bernell Jones, father of Cissie King-Jones (Arrowette) from the Young Justice comics. We also see his (unnamed) daughter, who is very impressed by the bow-slinging heroes.
Green Arrow stops criminals from robbing a "Save-Big" store, in a mirror of the first scene of Justice League Unlimited. The Save-Big itself is on the corner of Weisinger and Papp, who were the creators of Green Arrow.
The logo of the Justice League team is the logo of the Justice League animated series.
The six members of the League who go missing for 16 hours in "Auld Acquaintance" are Superman, Batman, Wonder Woman, Martian Manhunter, Hawkwoman and John Stewart, the primary cast of Justice League. According to series creator Greg Weisman, Flash was not included in the group so he could be present for Impulse's introduction in Season 2. (Besides, it would have been the wrong Flash; the JLU version was Wally.)
Incidentally, those six are the ones that comprised the Justice Lords, a group of alternate universe duplicates that went evil and took over the world. Which is fairly similar to what the missing six were supposed to have done.
In "Coldhearted" Batman mentions that the Watchtower is not weaponized, which may be a reference to how the Watchtower's Wave Motion Gun caused constant problems with the U.S. government in the Justice League cartoon.
In season 2, Batman refers to the Light as a "secret society of super-villains", which is the exact name of a similar group from the comics.
Jaime Reyes mentions that Captain Atom was the one who told him about Ted Kord, the previous Blue Beetle. In the comics, Captain Atom and Ted were both Charlton Comics characters, and the latter even debuted in a back-up feature in Captain Atom's series.
In "Bloodlines", Flash tells a woman and her son to hide out in a shelter located at "Fox and Gardner," a reference to prolific comic writer Gardner Fox.
In "Depths", Carol Ferris appears wearing violet, the primary color of her comic identity, Star Sapphire.
In "Satisfaction" Lex Luthor has a security guard named Otis.
Mal Duncan temporarily adopts the identity of the Guardian. This might be surprising unless you know that there was a time in the comics when he was the Guardian.
Virgil Hawkins, while talking to Black Canary, mentions that the Reach began their experiments on him by prodding him with "little static shocks" to start with before amping up the juice, making sure to emphasize the last two words.
"Juice" is a reference to the Black Vulcan Expy in Justice League Unlimited. Virgil himself serves as the Black Vulcan Expy in Young Justice.
The episode "Runaways" finally confirms that Asami Koizumi and "Ed" Dorado Junior complete the set references to the Superfriends ethnic heroes, being a gender-flipped Samurai and El Dorado with a more defined power set, respectively.
The Zeta Beams that the team and the League use to travel originally come from Adam Strange's comics, although they function somewhat differently.
Wally's black outfit is similar to the one he wears in the 2004 limited series Justice League Elite, which was also about a covert ops Justice League, only this one was closer to black ops. It's also similar to that of the Black Flash, The Grim Reaper for DC speedsters.
Issue #24 of the tie-in comic references Robin's Mad Libs Catch Phrase from the Adam West TV series when Dick cuts himself off after saying "Holy—!!"
Nephewism: Kid Flash is The Flash's nephew, Miss Martian is Martian Manhunter's niece, and Artemis is Green Arrow's niece. Averted with Artemis — Green Arrow just told her to use the "you're my niece" cover story because she didn't want to tell the team she was related to villains.
Nice Job Breaking It, Hero: M'gann's Mind Rape of Kaldur not only revealed to her he was a double agent, but left him in a catatonic state and probably cost the team their Reverse Mole. To a lesser extent, Nightwing's decision not to tell any more teammates than he needed to and Superboy's decision not to tell anyone that M'gann was making a habit of Mind Rape were also a major contributors to this.
Also with Superboy not telling anyone about M'gann's playing fast and loose with the Mind Rape, as it's unclear if anyone else on the team actually knows about those tendencies.
Also, in order to Mind Rape Kaldur, she shut off the team's psychic link. Given their reliance on it in team coordination, the fight against Black Beetle would have gone a lot better, or they would have concentrated more on holding him off until Blue Beetle could arrive. So a double dose of Nice Job Breaking It, Hero.
It's the gift that just keeps giving. In order to reverse his Mind Rape, Vandal Savage called in Psimon to sort Kaldur's brain out, so Artemis had to take him out non-lethally and get M'gann to do it instead, so now she's a prisoner and Psimon will expose them as soon as he wakes up. It's practically to the level of Disaster Dominoes.
In an unrelated example, nice job blowing up the alien lab in Luthorcorp... with security cameras still on and managing to catch your images... Arsenal. Not only did he blow a covert mission and get them caught on camera, said lab was growing food to help fight world hunger. That is going to be a PR nightmare when it breaks.
Nightwing kicking Arsenal off the Team in front of the Runaways causes them to abandon the Team and take Arsenal with them, ensuring the loss of four potential members.
Nice Job Fixing It, Villain: Mongul's invasion of Earth to keep it out of Reach hands forces the Reach to sacrifice two thirds of its fleet to counter Mongul's missile barrage and "protect their investment."
Nice to the Waiter: When the Flash and Zatara rescue Iris West-Allen from an alien invasion in "Failsafe," the first thing Iris does, after thanking the heroes, is ask Denny, her cameraman, if he is okay. She is visibly relieved, and smiles, when he gives a thumbs-up.
Averted, as the characters explicitly point out that the biology of different alien species renders them immune to threats that would endanger the others. That is why the Light uses magically enhanced biotechnology to get around the problem.
Later averted when Arsenal attempts to sedate Mongul. Mongul's only reponse is that it smells nice. It's never explicitly stated, but it's pretty clear that a sedative that works on humans won't work on something as drastically different as Mongul.
No Conservation of Energy: Averted. Zatanna explicitly mentions that magic can only happen when there is energy to fuel it, usually given by the spellcaster.
No MacGuffin, No Winner: When it becomes clear to Black Manta that he won't be able to steal Starro's frozen body, he angrily declares that no one will have it and blows it up. This turned out to be the contingency plan if he couldn't steal it.
No Sell: Red Arrow finds himself being hunted by Green Arrow, the Flash, and Aquaman. When disoriented, he takes a blind swing with his bow at the nearest silhouette, only to watch his bow splinter pointlessly on Aquaman's chest.
Nom de Mom: Cheshire/Jade Nguyen, due to issues with her father, Sportsmaster/Lawrence Crock.
Non Sequitur Distraction: After Arsenal wakes up and recaps everything that has happened since his capture, including an alien invasion, the formation of a team by all the sidekicks and Ollie growing a goatee:
Red Arrow: We try not to call ourselves sidekicks.
Not His Sled: Virtually everyone knows that Barry did a Heroic Sacrifice and gave the Flash name to Wally. Then the series finale recreates the famous scene from Crisis on Infinite Earths where the Flash has to counteract a deadly weapon by running, which will end up killing him. Except it's not Barry Allen's last run. It's Wally's.
Though its implied this happened in the original timeline where Impulse came from.
Not Quite Saved Enough: Impulse's Bad Future in "Bloodlines". Although the real reason for him coming back was to stop Blue Beetle from betraying the Earth, so only time will tell.
Considering the Reach's plans to conquer Earth are effectively ruined (though they're going to try and destroy it), he may have succeeded.
Though he might have just changed the Bad Future from the Reach conquering the Earth to Darkseid conquering the Earth.
Kid Flash says this in "Auld Acquaintance" when Black Canary questions why they have Red Tornado hooked up to his android alter-ego. When she points out the obvious transfer taking place, Kid Flash amends his statement to say it's exactly what it looks like.
Done much more seriously in "Salvage", when Red Arrow tries to defend stealing a wad of cash from a shopkeeper, specifically by pocketing it after stopping the thief who stole the rest.
Now Let Me Carry You: The Runaways rescuing the Team from the Reach in "The Hunt" after they rescued them in "Before the Dawn".
In season two, Superboy and Miss Martian split the difference: Miss Martian always has command of the squad in Nightwing's absence, but Superboy counsels with and advises him, with neither of them really stepping into the actual hierarchy.
At the end of the series finale, when Nightwing has both returned leadership to Aqualad and chosen to take a leave of absence after Wally's death, Batgirl is nominated as the team's new Number Two.
Numerological Motif: A 16-member Justice League, the setting is Earth-16, Miss Martian is 16 by Martian years, Superboy is 16 weeks old, Wally is woken up on his sixteenth birthday at sixteen minutes past the hour, the first season finale began at 00:16 hours on December 31st (and continues after the end of the opening exactly seven hours later at 07:16), and the end of the episode comes with the revelation that six members of the League, including the Big Three, were missing for 16 hours. The second season, which opens five years after the first, starts at 16:16, in the year 2016note Weisman used a 2010 calendar to figure the dates, meaning it was New Year's Day 2011 when the first season ended. Add the five year timeskip and the second season takes place in 2016. When asked about it, Weisman's only response was "<chuckles evilly>." He gave that response on August 16.
Episode 16 of season two aired on February 16, 2013.
The final episode of the series aired on March 16, 2013.
Oblivious Guilt Slinging: In "Satisfaction", Following Nightwing and Kid Flash faking Artemis' murder at the hands of Reverse Mole Aqualad. Mal Duncan says he is going to make the apparent villian pay for what he is done and Paula Crock thanks Wally for his emotional support through the worst days of her entire life, leaving Kid Flash and Nightwing feeling guilty for lying and putting their friends and loved ones through this.
Odango Hair: Cheshire sports this when in disguise in "Targets."
In the pilot, Kid Flash's reaction to seeing the doors close in front of him while he is at full speed and can not stop before running into them.
In "Targets", Red Arrow realizes the jail cell wall is going to explode about half a second before it does.
In "Terrors", Icicle Jr. sees the "Terror Twins" kissing and realizes that they are actually Superboy and Miss Martian in disguise and says, "Oh man, dad's gonna kill me."
In "Misplaced", Billy Batson's reaction to hearing that Amber, the pilot flying his plane, was about to turn 18 in the world where adults disappear. Two seconds before it happens.
In "Agenda", Captain Marvel gets this when the Flash and Wonder Woman begin to question his presence with the Justice League after they surmised that he was not an "adult" at all.
In "Usual Suspects", Red Arrow's reaction to discovering that he was the mole and while under Mind Control put the entire Justice League under Mind Control as well.
In "Auld Acquaintance", Vandal Savage has this reaction after realizing that Black Canary, Red Tornado, and Red Arrow weren't brought under control via the Starrotech he had just applied to them. As a result, he realizes that the Team had reverse engineered a cure and vaccine for Starrotech.
Subtle one in "Auld Acquaintence:" Robin is fighting Batman. When Robin's blow doesn't land on anything, he realizes that he lost sight of his opponent, and the turns his head with a grim sort of anticipation, clearly expecting it when he gets smacked aside a minute later.
In "Happy New Years", Blue Beetle's mere presence convinces a group of alien tech thieves to abandon their entire operation and self-destruct their base.
Artemis in "True Colors" when she learns that Psimon will be sifting through Kaldur's memories and finding out the truth about them being moles.
Nightwing in "The Fix" when Superboy reveals that, thanks to him keeping Kaldur's loyalties a secret, M'gann fried his brain, and they don't know if he can be fixed.
Also in "The Fix"; Artemis's continued mental repetition of the word "perfect" could very easily be replaced with the word crap. Here its less shocked and more painfully resigned.
Also from "The Fix"; Impulse's expression and tone when Jamie reveals that Green Beetle has silenced his Scarab.
In "The Runaways", guards from Star Labs surround a building that has the runaways inside. Cue Tye's gigantic astral form pushing the roof off.
Averted due to Martian Manhunter's fondness for the name John. He took the name John and came up with Red Tornado's name of John Smith. With Giovanni Zatara, who sometimes Anglicizes his name as "John," and Green Lantern John Stewart, that is four Justice League members named John. Martian Manhunter suggests that Superboy should also be named John, but that idea is turned down.
Clark Kent and Kent Nelson, which is Lampshaded: J'onn suggests "Kent" as Superboy's last name, but since Superboy and Megan do not know Superman's secret identity they assume it is in honor of Kent Nelson.
Superboy: Shouldn't I be Conner Nelson?
Played with in "Disordered". When introducing themselves one of the Forever People says his name doesn't translate to anything on Earth so he goes with "Wolf"... except Superboy has a wolf named Wolf with him, so he goes with "Bear" instead.
Only Fatal to Adults: "Misplaced" opens with Klarion and other immortal sorcerers casting a spell that causes everybody on the planet over the age of eighteen to disappear, leaving only the Team and Billy Batson (who cannot become Captain Marvel for fear of likewise being removed) to determine the cause. Halfway through the episode it is revealed that, to the adults, it looks like the kids are missing: Klarion and the other sorcerers split Earth into two separate dimensions, one with the adults and one with the children. Captain Marvel's transformation allows him to switch between worlds thanks to the age change.
Unlike the other members of the Team, Robin is always referred to as "Robin." It is explained that Robin was instructed by Batman to never reveal his true name in public. Jack Haly, owner of Haly's Circus, recognizes and calls him Dick. As he explains, there is no mistaking a Grayson on the trapeze.
Superboy, who does not have any other name, until "Targets", where he is dubbed "Conner Kent", since M'gann liked the name "Conner," after the love-interest in Hello Megan!, and J'onn suggested the last name "Kent." By season 2 Superman has since given him the Kryptonian name "Kon-El".
On The Rebound: La'gann was Miss Martian's "rebound guy" during her Off-Screen Breakup with Superboy during the Time Skip. He even gets called such on the series. She eventually dumps La'gann because she realizes that he's just a rebound guy to her.
Opinion Flipflop: Kid Flash changes his opinion on the existence of magic, which he believes to be nothing but technology obscured with false mysticism, as soon as he hears that M'gann believes it is real.
Opponent Switch: Superboy lets Icicle. Jr. fight Mammoth and Blockbuster so he could fight Mr. Freeze.
Order Versus Chaos: Turns up in "Denial", Dr. Fate works for the Lords of Order while Klarion is a Lord of Chaos.
Out-of-Character Alert: Batman refers to the Team as "kids" in the beginning of "Auld Acquaintance," which Robin recognizes is something he never does.
Tye realizes that something is wrong with Jaime when he lets Red Volcano take them as hostages. It's later confirmed his Scarab is now in control.
Overprotective Dad: Zatara is quite protective over his daughter Zatanna, seeing how she is a teenager and how weak she is in actual combat.
Dr. Desmond/Blockbuster's did not look at all pleasant. Helped to no end that it involves his skin ripping off.
After the test subject for the Blockbuster-Venom serum transforms, parts of his skin tear open and you can see exposed muscle underneath.
Blue Beetle getting the armor in a flashback in a variant. The only thing that really looks painful is the Scarab clamping itself to Jaime's spine, but the rest of the scene plays out like it's Body Horror.
Bruce Wayne is very much this to Dick Grayson. Dick actually gets jealous in one episode when Bruce privately lectures Aqualad after a disastrous mission. Bruce then alleviates Dick's concerns by playing basketball with him (claiming that it's "training"). Suprisingly enough, this series averts the parental relationship between Bruce and Alfred. Word of God states that Alfred deliberately remained emotionally distant from Bruce in his youth because he felt it was inappropriate for a butler to act as a father to his "master". Alfred regrets that and has since become closer to both Dick and Bruce.
Even though he rejected him in the beginning, Superman to Superboy does count as well.
Le Parkour: Kid Flash, in sort of a stumbly, not-always-exactly-as-intended way. Robin, on the other hand, is the stylish one.
Pineapple Surprise: In "Summit", Kid Flash pulls the pins on the smoke grenades being worn on the vests of three Light ninjas.
Pinocchio Syndrome: Discussed and lampshaded in "Humanity". The first three members of the "Red family" ultimately get this, which leads to T.O. Morrow declaring them as failures; Red Volcano is only one designed NOT to have it, which results in him turning on his "father".
Please Put Some Clothes On: A variation. When the Team finds out about Red Tornado's "civilian identity" android, Zatanna magically transforms the sheet that was covering it into pants, which she felt it needed.
Plot Armor: The Light has never gone all-out to try and destroy the League or the team, although Blue Beetle II and Aquagirl both died fighting them. With the League, it's implied they want to use them as scapegoats, while Summit makes clear that the team is alive primarily because the Light, for all their planning, simply doesn't view them as a threat.
Plot Hole: When the League is brainwashed by the Light and sent off to wreak some havoc they later discover that they have no memory of what they did and spend five years trying to find out, completely overlooking the possibility that they could ask the GL Corps, or even the ring itself. Even if they turned up to be a dead end, it's still a better place to ask around about the whereabouts or activities of a certain green clad ringwearer than anywhere else, especially anywhere on Earth. Weissman completely dodged the question, making vague claims about the government of the attacked planet being corrupt, but it seems like one of their guys being Brainwashed and Crazy and in possession of the strongest weapon in the universe would be a big issue for the Guardians, regardless of whether the planet would tell them they were attacked.
John Stewart: Hey ring/Salaak, what happened to me in the last X hours? Kthxbai."
The team's ability to defeat Green Beetle when they were in Bialya to cure Blue Beetle. In addition to having all of the same tricks that Black Beetle (who can basically solo most of the team) Green also has all of his Martian abilities as well, but they were able to incapacitate him with no real effort.
Plot-Relevant Age-Up: Superboy, who's only 16 weeks old at the start of the series, but had already been aged to an adolescent by Cadmus so they could "weaponize" him.
Pokémon Speak: Secret, since the last thing she saw before her brother killed her was a neon sign that said "Secret."
Polite Villains, Rude Heroes: In "Targets", Lex Luthor and Red Arrow have this relationship, Luthor maintaining his unerring politeness at all times, and Red Arrow being his usual snarky, jerkass self. This actually happens between Luthor and every superhero he meets, including his own genetic son, Superboy.
The G-gnomes telepathy causes their horns to glow red.
M'gann's eyes at times.
Power Echoes: When Kid Flash gets stuck inside Dr Fate's helmet and meets Kent Nelson's spirit, this happens to both of them... except the echoes sound a few seconds before they start speaking. It takes you a fair while to realise something is wrong.
Power Nullifier: Belle Reve's combination nullifier/shock collars, which nullify preprogrammed powers and can can shock the wearer on command. The downside is that they only nullify those powers they have been programmed for, so any unexpected powers are unimpeded.
Power Parasite: The Parasite, naturally. Unfortunately for him, the weaknesses and strengths come as a package deal.
Power Perversion Potential: Miss Martian shapeshifts into Black Canary for a little roleplay with Conner, and such behavior is apparently very common on Mars since shapeshifting telepaths can't actually hide who they are from others. Green Arrow thought it was pretty funny, though Canary didn't.
Power Tattoo: Aqualad's, and other Atlantean's, light up when he is using his hard water powers or electric powers.
Pregnant Badass: Aquaman reveals that his wife, the Queen of Atlantis, is pregnant, and just a few minutes later she is kicking all sorts of ass when her city is attacked. Admittedly, she's only a few months along (the episode takes place in late August, and Word of God says she is due in February).
Present Company Excluded: Comes up when Kid Flash makes a comment about aliens, then is obligated to apologize to Conner and M'gann.
Properly Paranoid: In "Terrors", Batman doesn't let the Belle Reve prison staff know that Superboy and Miss Martian are going in undercover since it's possible the prison staff has been compromised. The ending reveals that the breakout was part of the prison psychiatrist Hugo Strange's scheme to become the new warden of Belle Reve.
Psychic Link: Miss Martian often connects the Team telepathically while on missions, letting them communicate covertly over distances. Eventually, the group begins using this method of communication even outside of battle when they want to have private conversations.
Put on a Bus: Eight of the League members, the majority of whom were mentors to members of the Team, leave Earth at the end of "Alienated" to face trial in an intergalactic court for the crimes they committed 5 years prior while under Mind Control.