The first animated series starring the Teenage Mutant Ninja Turtles, and the one responsible for the worldwide turtles phenomenon. It lasted from 1987 to 1996.The story goes something like this: Hamato Yoshi and Oroku Saki were members of the Foot Clan. Out of jealousy, Saki compromises Yoshi's position in the clan and forces him into exile. Escaping to the New York sewers, Yoshi eventually makes pets of rats living there, as well as four baby turtles which happened to fall inside.One day, Yoshi finds the turtles immersed in pink-colored ooze, which he gets all over himself while trying to clean it off. Soon, he finds the turtles growing to humanoid size, and himself turning into a humanoid rat; the ooze, which had been spilled by Saki in order to kill Yoshi, was a mutagen that would grant an organism traits from the previous organism it had come into physical contact with. Yoshi decides to raise the turtles, name them, and train them in the martial arts.Eventually, the turtles rescue April O'Neil, a reporter covering a crime wave seemingly committed by ninjas. With her help, they discover that Oroku Saki, now calling himself the Shredder, had taken control of the Foot Clan, and had allied himself with exiled warlord Krang in order to conquer the world. The turtles, naturally, vow to stop him, and obtain a way to restore Hamato Yoshi—now named Splinter "for obvious reasons"—to his human form.Unlike the comic book that inspired it, the tone of the cartoon was for the most part more akin to a sitcom than an action series. The turtles were more liable to crack wise than act like the ninjas they supposedly were. The main villain group shared a sitcom dynamic, with Villain Decay setting in almost immediately. Many episodes were Strictly Formula, using whatever stock plots the producers had handy.After seven seasons, the series was retooled in an attempt to make them more serious. The palette was darker, the Shredder and company were eventually Put on a Bus and were replaced by the alien Lord Dregg and his posse, and the tone became less humorous. Reactions to the "red sky" seasons remain mixed; while some appreciate the shift, others believe it took away from the series' strengths. This new direction lasted for three 8-episode seasons, until the series' end in 1996.Despite—or perhaps because of—the numerous changes made to the source material, the series became wildly popular, providing the thrust behind a massive toy line, inspiring the Teenage Mutant Samurai Wombats cartoon subgenre, and even getting a two-part OVA in Japan. The series continues to influence the franchise today, with every later incarnation of the turtles maintaining at least part of the tone of the series, as well as multiple nods to it.Thirteen years after its end, the series received a brief revival in Turtles Forever, a crossover between this incarnation of the Turtles and their counterparts from the 2003 series.See also: Teenage Mutant Ninja Turtles (franchise page), the franchise character sheet, and the page for Teenage Mutant Ninja Turtles Adventures, the comic book based on the animated series.
This incarnation of the Ninja Turtles includes examples of:
Aborted Arc: Season 8 set up several possibly new enemies and allies for the Turtles — all of whom were promptly forgotten about in the following season in favor of Dregg and Carter.
It also ended with the implication that members of H.A.V.O.C. were still on the loose and that April would do something important in the far future, things that were never brought up again in Seasons 9 and 10.
Although Mona Lisa appeared in just one episode, it was implied her storyline was just beginning.
Absolute Cleavage: Subverted: Although April's jumpsuit was occasionally left open enough for this trope depending on the artist, her cleavage was usually left undrawn whenever this happened, as seen in her character◊ model◊note The first one is from the original cartoon and the second is its Turtles Forever reproduction. Fan artists, on the other hand...
Adaptational Villainy: Leatherhead, who was an ally in other continuities (though it was common for him to start off as having a misunderstanding with the Turtles). Also Wingnut and Screwloose, who originated as allies in the Archie Comics series Teenage Mutant Ninja Turtles Adventures, but here appeared as one-shot villains in the episode Zach and the Alien Invaders.
And I Must Scream/Fate Worse than Death: Synapse in the Red Sky episode H.A.V.O.C. In The Streets. Donatello defeats the electric mutant created by Titanus by sending him through a ham radio, leaving him permanently trapped on the radio airwaves forever.
Implied to be Baxter's final fate in Revenge of The Fly!. Poor guy...
Animation Bump: More times than possibly any cartoon in the 80's and 90's. The animation style could go from being horrible to decent to near-anime quality, sometimes in a single episode. The first two seasons each kept with a single animation studio (Toei for Season 1, and A-1 Productions for Season 2), but the seasons grew much longer starting with Season 3, resulting in animation being farmed out to several different studios note Wang Film Productions, Pacific Rim Animation, Luk Film, Kyung Kang, Island Animation, Varga Studios and Hanho Heung-Up, with an occasional episode by Toei, none of them credited. This continued until the "Red Sky" era, where the seasons got cut down to eight episodes each and a single studio (this time Dai Won Animationnote and Morning Sun for season nine) became sufficient to handle all the show's animation again.
On top of that, a number of Season 3 episodes and the entire first half of Season 4 was farmed out to Murakami-Wolf-Swenson's studio in Ireland. Some of the episodes ("Turtles in the Jungle" for instance) turned out pretty decent, but most of these outsourced episodes were among the worst-animated in the show's run. Likewise, the "Vacation in Europe" episodes were farmed out to French studio IDDH on a smaller budget than usual, and suffer particularly for it.
Anime Hair: The Neutrinos take this to ridiculous extremes.
Animesque: The first season had a very obvious anime influence — unusually though, it was for reasons of practicality rather than artistic preferences. The show's original character designer, Ira Turek came up with a load of character designs which were butt ugly and nearly impossible to animate well, resulting in him being fired. He was replaced at the last minute by Peter Chung, who redesigned the primary characters to have a more Anime-inspired look in order to ensure that the Toei Animation team would be able to work with them. The following seasons largely ditched the animesque character designs.
There was also Bug-Man who only showed up in one episode. He was an insect-themed superhero who curiously turned into a powerful superhuman when angered. In the episode, he had become a pacifist but since Michelangel needed his help, he tried his best to make him angry so he would turn into his super-powered form.
Seasons 6 and 7 also have surprisingly improved animation.
Artistic License - Engineering: In The Big Zipp Attack, Shredder and co. try to steal the top of a metal spike from the roof of a building. If the spike's top is removed, the entire building will fall over, as the construction of the building is somehow completely dependent on the top of the spike staying in place (even though the spike itself more or less resembles an antenna mast sticking out of a flat rooftop).
Artistic License - Physics: Mona Lisa explains to Raphael that she was a college student that was going for her physics major, but in the flashback she is clearly using a chemistry set.
Ascended Extra: The Shredder was killed in the first issue of the original comic. (Although he came back a few times, including in the form of a giant, mutant shark.) Here, he collaborates with Krang as the longtime Big Bad of the series.
As You Know: Spoofed in the episode Super Rocksteady and Mighty Bebop:
Shredder: Only mutants are immune to the Mesmerizer's beam; humans like myself can't be near it when they set it off!
Krang: You don't have to explain it to me; I invented it, remember?
Shredder: I wasn't explaining it to you... (points at the camera) I was explaining it to them.
And again in season 5's Enter Mutagen Man:
Krang: We must have that mutagen ready before the rocket takes off this afternoon!"
Shredder: I know, I know, you don't have to tell me!
Krang: I'M NOT! (looks at camera) I'm telling the audience.
Atlantis: Plays a part in the episodes "The Lost Queen of Atlantis" and "Atlantis Awakes".
Also, Krang's robotic body was able to grow into this until the Ninja Turtles broke the microchip that enabled it to.
In "Turtles Of The Jungle", a scientist accidentally enlarges a monkey, then enlarges Don to stop him.
"Big Bug Blunder" had several giant bugs, created somewhat by accident by Shredder, Bebop, and Rocksteady (What I mean is it was their intention to make an army of giant ants, but instead Bebop and Rocksteady wasted most of Krang's chemical on only a couple of insects), which included an ant, a praying mantis, a wasp, and a fly. Cue giant monster fight.
Awesome, but Impractical: The Technodrome. Virtually unstoppable on occasion, but virtually unstartable the rest of the time, as its heavy fuel requirements and tendency to get stuck in various remote locations make it hard to manage.
Back Up Twin: Barney Stockman would probably be this if he appeared more than once.
Bad Future: Inverted in Once Upon A Time Machine, where the future is bright, clean and peaceful, because the Turtles did away with Shredder, Krang and their forces. Even the former members of the same gang as Bebop and Rocksteady took to living a life without crime. That is, until Bebop and Rocksteady get their former gang into the future, where there seems no law enforcement (or need thereof). The turtles, though, see themselves as not having aged well at all.
Body Swap: The Old Switcheroo, with Splinter and Shredder.
Subverted in "Cowabunga Shredhead" with Shredder believing himself to be Michaelangelo. The entire episode is a Crowning Moment of Funny.
Also Raphael Drives Them Wild, with Raphael and Oscar the cab driver.
Bond Villain Stupidity: The Shredder proves himself more than a match for the turtles in armed combat, yet on many occasions when confronted he 'escapes', often with the words "another time turtles!" Why another time? Why not now!?
Bowdlerise: Over in the UK, Ireland and Germany, "ninja" has until more recently been a banned word, so the series (as well as the franchise as a whole) would be known as Teenage Mutant Hero Turtles. Also, all scenes where Mikey wields his signature nunchuks were cut as much as possible due to the weapon being illegal in real-life. By the later seasons, the series would see Mikey using a grappling-hook weapon instead just to get around these kind of problems.
Although, the first few seasons of Teenage Mutant Ninja Turtles were eventually released uncensored on DVD in the UK.
Butt Monkey: Baxter Stockman. Unlike the original comic villain, who was his own entity, here Baxter is a shaky ally of Shredder, who eventually swears vengeance against both him and the turtles after they make his life a living hell. This status even carried over to his counterpart in the 2003 show; albeit in Darker and Edgier form.
Bebop and Rocksteady can never catch a break.
Not to mention Vernon. If anything bad happens to someone at Channel 6, you can bet he'll be the first person on the receiving end. But he usually deserves it anyway.
Chuck Cunningham Syndrome: Happened quite frequently. Nearly every episode would introduce a new ally of the turtles or a villain who swears revenge after being defeated, only to never be seen again. Many of the characters from the Lighter and Softer earlier seasons(The Punk Frogs, The Neutrinos, and Mondo Gecko, etc.) were nowhere to be seen in the Darker and Edgier Red Sky seasons.
City of Weirdos: Giant humanoid turtles fighting an army of mooks, flying around town in a giant blimp, and regularly appearing on the local television news doesn't warrant much comment or outrage from the locals.
Color-Coded Characters: In the Mirage comics, the Turtles all wore red bandanas (not that it mattered much in a black-and-white comic), leaving their distinct weapons as usually the best way to tell them apart. Obviously, this series didn't go that way - giving Leonardo blue, Donatello purple and Michaelangelo orange, while Raphael kept red. All succeeding adaptations have maintained this approach.
Composite Character: In the original comics, Hamato Yoshi was murdered and his pet rat became mutated into Splinter. In this version, Yoshi himself is mutated into a rat-man. A rather poignant episode lampshaded the fact that Splinter was pretty lonely because of this, since he couldn't interact with other humans anymore.
Convection Schmonvection: Lava arguably made more appearances than the teens from Dimension X in this show, but one particularly blatant incident occurs in an episode where a rock soldier accidentally knocks a special welding material into lava, turning the lava into an unknown yellow goo. Shredder inspects this substance by STICKING HIS HAND INTO IT AND PULLING SOME OUT. Hilariously, while he's standing right next to a red-hot puddle of lava, he does complain about the heat, but apparently the goo is cool to the touch. Suspension of disbelief aside, who sticks their bare hand into mysterious geletanous substances like tha... oh. right. Splinter.
Correspondence Course: Donatello used one to further his education beyond super genius, only to run into problems with getting the degree itself: he has to pick it up in person, and the university mistook him for "Miss Dona Tello". It turns out the owner of the university was looking for a mate as part of a Genius Breeding Act, which is why he wanted "Dona" to appear in person.
Demoted to Extra: After Carter showed up, April was relegated to sitting in her apartment and researching stuff on the internet for all of Season 9 and the first few episodes of Season 10. Fortunately, she started taking a more active role in the final few episodes once Carter was written out.
Delusions of Doghood: It's heavily implied (if not outright stated) that the Rat King actually believes himself to be a rat.
Depending on the Writer: Every single character is subject to change. Poor Leonardo go hit by this the hardest and never seemed able to keep a consistent personality.
The Dragon: Rocksteady and Bebop were Co-Dragons to The Shredder. Baxter Stockman was Shredder's Dragon for the first half of the second season.
In the Red Sky seasons, Hi-Tech was Lord Dregg's Dragon in Season 9. He was later replaced by Mung in Season 10.
Dragon-in-Chief: The Shredder sometimes falls into this starting in season 2(though he's still the Big Bad, while Krang is a Bigger Bad), though the relationship between him and Krang is basically a Big Bad Duumvirate since the plan seems to be for both of them to rule the world.
Early-Installment Weirdness: A relatively mild case — the show's tone and overall storyline remained pretty much intact from the first few episodes until the "Red Sky" era. The big differences were in the way the first season was animated, with a much more obvious anime/manga influence, but also being prone to moments of sloppiness and Off Model characters. Raphael was also more similar to his comic counterpart initially, to the point where he threatened to kill Baxter Stockman if he wouldn't tell the turtles where Shredder was.
In his 1st few appearances, Krang was undisputed Nightmare Fuel. His later character design was a lot more cartoony, but still a bit creepy.
Enfante Terrible: Shredder, as shown in the clips of his life from "Shredderville".
Face-Heel Turn: Shortly before the entire Channel 6 staff was Put on a Bus, Vernon Fenwick ends up siding with Burne Thompson, and agreeing that the Turtles are a menace to society, and all because they didn't save the Channel 6 building from Shredder's explosive device in time.
False Reassurance: This exchange from Shredderville, when the Turtles encounter the unmutated Bebop and Rocksteady.
Fan Nickname: "Clonatello" or "Duplicatello" for Donatello's Evil Twin duplicate he creates in "Donatello's Duplicate".
Fatal Flaw / Foreshadowing: The Turtles' bad future selves in "Once Upon A Time Machine" turn out to be everything Splinter warned them against earlier on. Specifically, Donatello turning blind from reading in poor light, Raphael's inability to work from excessively watching television, and Michelangelo's eating disorder.
For Halloween, I Am Going as Myself: At the beginning of Super Irma, the Turtles don't know what they should wear to the Channel 6 Halloween party. Splinter suggests that they go as themselves, and they do.
Flanderization: Bebop and Rocksteady weren't exactly smart in the first season, but were portrayed as serious threats to the turtles. Later seasons toned up their stupidity to ridiculous degrees, and made them even more incompetent.
When the Turtles point at something, they use their middle finger (it doesn't help that they only have three fingers on each hand).
In one episode, Shredder said, "Let me give you a hand... or better yet, a finger!"
When April is taken hostage alongside the Turtles in one episode and is asked on any last words, she says, "I can think of a few, but they're not appropriate for television."
The end of the first act of "The Lost Queen Of Atlantis" has a freeze frame of Shredder taking a magic amulet off of April while she's being restrained, which from the angle of the shot looks like he's grabbing April's breastand maniacally laughing at the same time.
Raphael once said "Come on, chipheads!" "Chipheads" sounds oddly like "shitheads".
As the group confronts Krang's body in one episode, Raph says, "Hurry up! We can't hold this bucking bag of bolts much longer!"
Leatherhead called the turtles "possum pussies" at one point. No, really.
Highly-Visible Ninja: The turtles, who can frequently be seeing putting around on a blimp. With a giant "Turtles" on it.
Not to mention the Turtle Van, which was customized with armored plates resembling turtle shells and laser turrets on the roof.
The Turtles themselves weren't quite that astute at not letting people see them, they were known by the general public (it probably didn't help that April kept filming them though). Even Shredder, a proclaimed "ninja master", wore outlandish Samurai armor and would often broadcast threats with as much publicity as Dr. Doom.
Hollywood Pudgy: From time to time, Irma will mention being on a diet, and although her size is mostly obscured by a baggy turtleneck sweater, on the few occasions she wears something else, it's clear that she certainly isn't even fat at all.
Hot Goddess: April wearing a magical amulet in the episode "The Lost Queen Of Atlantis".
Humanity Ensues: Temporarily occurs to Michelangelo in the episode The Gang's All Here.
Hurricane of Puns: The episode "Mutagen Monster", where the mere presence of a mutated bull leads the episode to be full of cow puns. Raphael even says the Wendy's slogan "Where's the Beef?" in the same voice as in the commercial.
Hypocritical Humor: In the first episode, The Shredder, upon seeing the Turtles, says to himself that the Turtles must not discover his Technodrome. He then proceeds to loudly announce "All Foot Soldiers return to the Technodrome". And yes, the Turtles manage to hear the announcement.
Likes Older Women: Michaelangelo has been shown to have a little bit of a crush on April, despite only being a teenager and she's nearly thirty, though this is completely justified considering her appearance.
Also Donatello shows the same signs as Michaelangelo towards April which are once again justified, but this is inverted with Irma who seems to have a slight crush on him at times.
Raphael for Mona Lisa, considering that he's still somewhere in his mid teens, and she's a college student who's probably in her late teens.
Leonardo for Lotus Blossom also applies.
Lighter and Fluffier: Especially in comparison to the original comics, but also the first season compared to most of the ones that followed, and in turn those seasons compared to the "Red Sky" seasons.
Having said that, the series was still criticized for being Darker and Edgier compared to most other animated shows at the time. Considering the restrictions the creators had to work under, it's actually a small miracle that the series didn't end up a total bastardization of the original comics.
Peter Laird said in an interview that, faced with the reality of needing to water down his creation for a younger audience, he largely let the show's staff do it for him. This may have been a wise choice on his part, as had he tried to do a more comic-acurate version in the face of the rigid censorship of The Eighties, it quite possibly would have come off as a total bastardization of the comics. As it was, it came off as an extremely loose adaptation but very entertaining when taken as its own entity.
Raph and Shredder also fall under this trope, with Raph being far less hot-headed (and more sarcastic) and Shredder being more ineffectual and comedic (although still skilled at martial arts and a potential threat).
Long Runners: With nine years, ten seasons, and almost two hundred episodes to its name, this was the Gunsmoke of Saturday morning cartoons. It was the longest running cartoon until The Simpsons came along.
A squickier example is the canonically fifty-year-old Burne and his girlfriend Tiffany, who looks nineteen.
Meaningful Echo: In the first episode of the Red Sky series, Shedder and his minions are pinned down by police as they try to retrive a device they need. Shredder hurls a trashcan which he says are filled with explosives at the cops, causing them to scatter. After they make their escape, Bebop and Rocksteady compliment him on his bluff. The trashcan explodes in the back ground, with Shredder stating, "I never bluff." Much later, Shredder has taken the Channel 6 building hostage, and has to threatened to blow it up if the Turtles don't meet him in a certain amount of time. When they get there, they see that the building is still standing, causing them to assume he was bluffing. What does Shredder have to say? "I never bluff." What follows is easily the most dramatic moment in the series.
Meaningless Villain Victory: In "April Fool" Shredder manages to get away with a rare isotope. Unfortunately for the bad guys, the isotope is unstable under high atmospheric pressures (especially those deep within the Earth), and the sample explodes after the Shredder returns to the Technodrome parked many miles beneath the Earth's surface.
Monster of the Week: More common in the earlier seasons, the turtles would often fight a new one-shot villain that either has a connection with Shredder and Krang or is working of their own accord. Alien warlords, other mutants, criminal gangs, evil robots, mad scientists. Name it, and chances are the turtles have faced them at least once.
Even better: Michelangeo's nunchuku are taboo in the opening. Every scene of him swinging his weapons is cut or replaced with other footage. Even a closeup of his hand holding a nunchuku is gone. Oh, but Leonardo cutting the screen in two? No problem!
Maybe they thought nunchakus are dangerous even if they're home-made and hand-made, unlike the sharper hand weapons?
Fighting can be heroic, ninjas are just assasins and nunchucks were outlawed at the time due to gang use and the ease of which they could be made and used in schools whereas swords (which also have heroic connotations unlike nunchucks) and sais weren't.
The best bit is that everyone in Britain called and calls them the Teenage Mutant Ninja Turtles anyway.
Motive Decay: This is explicitly pointed out with Dregg. At first he's just trying to take over the world. By the last episode, the turtles have thwarted his schemes so much that he's driven purely by the desire to kill them. Even his right-hand henchman calls him crazy to his face.
Mysterious Past: We know absolutely nothing about the Rat King's backstory.
Krang too. What little we know of him actually seems to contradict itself.
Name's the Same: In season eight, there's a villain named Megavolt, who shares the same name as another villainous character named Megavolt.
There's also some Fridge Brilliance in that episode since Megavolt wanted to destroy the D.W.(Dark Water) company out of revenge. D.W. is also the nickname of Darkwing Duck.
Also Baxter Stockman's Mouser robots have the same name as King Koopa (Bowser)'s assistant in Super Mario Bros..
The Other Darrin: Several voice actors would occasionally have replacements during particular episodes:
Shredder was the biggest example, due to James Avery's other work; he was substituted by Dorian Harewood for a lot of the later Season 3 episodes, and them Jim Cummings on and off for the next few seasons. He finally bailed out the show for good at the start of Season 7; Townsend Coleman (the voice of Mikey and the Rat King) voiced him for the rest of that season, and William E. Martin took over the role permanently in Seasons 8-10.
Raphael also had a few different voice actors over the course of the show; Thom Pinto voiced him for a few Season 3 episodes, Hal Rayle filled in for the "Vacation in Europe" episodes, and Michael Gough (no, not that one) replaced Rob Paulsen for the final season.
Donatello and Bebop, who were both usually voiced by Barry Gordon, were also replaced for part of Season 3 (seeing a pattern here?) by Greg Berg.
Vernon Fenwick was voiced by Pat Fraley in Season 1, but for some reason changed to being voiced by Peter Renaday starting with Season 2.
Out of Order: Episodes 3 and 4 were shown the other way around on VHS, so kids who didn't see them when they first aired on TV (stations didn't re-air the earliest episodes often) would often wind up confused about who this Baxter Stockman fellow was.
Also, a lot of the episodes on DVD are out of order too.
More than that, several episodes, (especially in season 4 and the vacation arc) don't make sense in their original airing order, and even have some continuity errors. "Tower of Power", the premier of the vacation arc, shows the Turtles leaving for Europe, and foiling one of Shredder's plans in Paris, but its the *next* episode "Rust Never Sleeps" that shows Shredder actually learning of the Turtles trip to Europe. In another example, "The Dimension X Story" which aired 3/4ths of the way through season 4, has the characters surprised that Shredder has found a way to return to Earth, even though its been happening all season. It also shows the turtles' dimensional portal blowing up, an event that was mentioned specifically in the episode that aired *before* it.
The Episode "Leonardo is Missing" which aired 3/4ths of the way through season 6, is obviously a displaced season 5 episode, as the technodrome is still stuck in the arctic, rather than being at the bottom of the sea.
Parenthetical Swearing: After Shredder destroys the Channel 6 building, with the turtles thinking their friends were still inside Leonardo's line "You miserable maggot!" is said with so much bile and restrained fury that one can easily hear him say "You lousy son of a bitch!"
Race Lift: Baxter Stockman, from African American to Caucasian (and vaguely European), because the writers didn't think that having the only black person in the cast be a villain would sit too well with audiences.
Another reason in Baxter's case is that the writers feared that Shredder constantly abusing his black assistant would be seen as racist.
Although many people forget that Bebop was African American before his mutation.
Also Lord Dregg, who naturally has red glowing eyes.
Also the Rat King in the Red Sky episodes. Earlier, he was morally ambiguous, helping both the Turtles and their friends, as well as Shredder and his associates. Once his eyes began to glow red, he was totally evil.
Red Sky, Take Warning: While there's no explanation for the skies turning red, things took a turn for the worse once they did- for the Turtles and their city. Either way, it's a warning for the viewers- the show wasn't as much fun since the change.
Reptiles Are Abhorrent: The main turtles, having sufficient Turtle Power, are depicted with minimal reptilian features. Other characters, like Slash and Leatherhead, may have more pronounced reptilian traits (scales, spikes, claws).
Retcon: The third season finale showed the Technodrome being destroyed as a result of an inadvertent attack by Krang's allies, and then crashing at high-speed into a huge battlestation. The fourth season premiere changed this to the Technodrome being badly damaged in the attack and then having a relatively soft landing on an asteroid.
Schmuck Bait: In the episode Shredder's Mom, Shredder's mom was able to trick the turtles into walking right into the Technodrome's trash compactor by taping a paper sign that said "This way to computer room" on the door.
To Leave It to Beaver, in an episode that had Beaver and Wally Cleaver reimagined as mobsters. No, seriously.
Also the monsters in the episode The Case Of The Killer Pizzas look a lot like another famous movie monster.
The episode Night Of The Dark Turtle is an obvious parody of Batman.
Rex-1 from the episode New York's Shiniest is pretty much a redesigned Robocop.
One episode had Krang stealing a military robot that looks like ED-209.
Irma Langenstein doesn't look like Jeanette of The Chipettes by accident... half a season of Alvin and the Chipmunks was animated by Murakami-Wolf-Swenson (the other half was animated by DiC Entertainment), then Irma was introduced on TMNT the following season.
Many references to monster movies, which the Turtles are always seen tuning in to on TV. Heck, some of the episode titles even sound like the names of B-movies. Examples of such titles:
The episode "Rondo in New York" is a tribute to the Universal Horror monsters and also has an Expy of Rambo that is named Rondo. Krang and Shredder use a substance to bring Rondo, originally just a movie character, into the real world (alongside all the other movie characters).
At the end of one episode, Leonardo says "There's no place like home", as a reference to The Wizard of Oz. The movie is referenced in another episode where a hologram of Donatello says like the Wicked Witch of the West, "I'm melting! I'm melting!"
In an episode where the Punk Frogs confront Leatherhead, one says, "Who you gonna call? Gatorbusters?
The Terminator is referenced in one episode when the turtles see a version of The Ahnold saying in a thick Austrian accent, "I'll be back!"
When the Turtles are seen playing video games, sometimes the sound effects are taken from the ill-fated Atari 2600 version of Video Game/Pac-Man.
From "Turtles on Trial", Bebop and Rocksteady are seen watching The Slurps, a thinly disguised parody of The Smurfs.
Word of God (David Wise) has admitted April's yellow jumpsuit and minicamcorder outfit was based on Fujiko Mine's outfit from the Japanese anime Lupin the Third. Specifically, her outfit in The Castle of Cagliostro.
The Polarisoid's camera, which captures the target and traps it inside, is a parody of the Polaroid camera, which takes a photograph and prints it instantly.
Sibling Yin-Yang: The villainous Shredder's younger brother Kazuo Saki is actually a cop fighting for justice.
Sinister Schnoz: Granitor, the gray Rock Soldier from the episode Hot-Rodding Teenagers from Dimension X.
Snow Means Cold: In Take Me to Your Leader, Shredder and Krang use a Solar Siphon to drain the sun's energy and make the Earth cold. The turtles discover something's amiss when it starts snowing in July.
Soap Within a Show: Krang is shown to have a specific fondness for a soap opera of the "Oh John! Oh Marsha!" variety. In fact, that's pretty much all the show seems to be.
Spared by the Adaptation: Hamato Yoshi. Originally, he was killed. In this series, he was instead turned into a rat-like mutant.
Also Buffy Shellhammer, who was able to use Shredder's own technology against him and trick him into making the wrong formula to free the Technodrome. Instead of rocket fuel, it turned out to be firework fuel.
Also Vernon's nephew Foster Fenwick, who creates a solar magnet that is actually powerful enough to draw the Earth towards the sun. Subverted as he's stated to be 11.
The Lava Caves Of New York: Trope Codifier. For something often surrounded by lava, the turtles don't have to walk very far underground in order to find the Technodrome. In fact, a few times, lava lakes apparently existed just below the sewers (if not in them)
This Is a Drill: The transport modules that Shredder and the other villains used most of the time.
The Only One Allowed to Defeat You: Shredder's attitude towards Splinter and the Turtles, so much so that they taunt him with it over the interstellar radio from a slave camp on Dimension X. His twisted code of ninja ethics forces him to bring them back to Earth...where they proceed to defeat Krang's bid for global domination.
Also Shredder, when he's the chairman of Octopus Inc. He actually gets things right, with frightening (for the Turtles) results. Until a sprinkling of water changes things. This was before the Red Sky seasons.
Wasn't That Fun?: One of the episodes in the final season sees the Turtles go off a waterfall, which then sees Mikey saying "let's do it again!"
Wait, What? Whoa: In Burne's Blues, Burne and Vernon spend the entire episode unsuccessfully looking for a news story about the Turtles. Just as soon as the reporters find the Turtles frozen on a factory loading dock, the two get randomly abducted by aliens that look like Elvis.
Wham Line: "I never bluff!" The line Shredder says before he destroys the Channel 6 news building in the first episode of season eight.
Also in "Donatello's Degree", the end of the first act features Donatello being attacked by two nerdy henchmen of the Big Bad and saying that they must be joking to take him on. The henchmen quickly bulk up and respond "If we're joking,then you're about to ''die'' laughing!
And in "My Brother The Bad Guy", the end of the second act has Splinter facing off against the Kojima Brothers, who were recently resurrected and saying that they have been deceased for centuries and that he doesn't believe in ghosts. The Kojima Brothers response to Splinter is "It is not necessary for you to believe in us for us to destroy you!"
Wham Episode: The first episode of season eight Get Shredder mainly because of the ending where Shredder destroys the Channel 6 news building.
"Enter: The Fly" initially starts out with the status quo from the second season: Shredder attempting to cause mayhem with whatever help he can get from Baxter thanks to Krang cutting him off in the premiere. Then quickly everything changes, as Bebop and Rocksteady return to take their place at the Shredder's side while he regains access to Krang's armament, Shredder attempts to by trying to kill April (not capture mind you, but KILL), and a botched attempt by Krang to vaporize Baxter cause him to instead be transformed into a half-human, half-fly creature in one of the most disturbing scenes in the show.