It's actually a Word of God rule: No outside force can harm the Coyote — only his own ineptitude or the failure of Acme products.
Trucks and trains were the exception from time to time. Even then, he's usually put in their path by his own plans/devices.
In a Citizen Kane themed episode of Tiny Toon Adventures, Buster enlisted Babs and Plucky to discredit Montana Max after Max framed Buster for cheating on an exam by planting a false book of answers. The title is actually lampshaded by Babs and Plucky.
Buster: C'mon guys, it's time to hoist Monty by his own petard!
Babs: What's a petard?
Plucky: I hope it's not heavy to hoist; I'm hernia prone.
In the Codename: Kids Next Door episode "Operation C.R.I.M.E.", the Villain of the Week was a kid who was supposedly a psychic who would predict crimes by using crayons to draw what bad thing the students at Gallagher Elementary are about to do. However, it turns out it was a lie, so that the kid can be the only one to get pizza bagels in the cafeteria, but unfortunately, it was lima bean sandwich day.
Though he survives, it's his own love for opera that undoes the villain's plan in An American Tail 2. How? Watch it for yourself.
Not to mention it was his own secret weapon that shot him and his cronies out of town.
In The Addams Family, Gomez Addams used the scissors of a member of a gang on the entire gang. The owner got promptly chased afterward when Mr. Addams explained, "Why blame me? He's the one with the scissors."
In Avatar: The Last Airbender , Zhao plans to conquer the Water Tribe by capturing the moon spirit (in the form of a koi fish) to cut off their ability to waterbend, rendering them defenseless. They end up anything but defenseless when he kills the spirit and enrages its companion, the ocean spirit, enough to use Aang as a medium to become a giant water monster, wipe out Zhao's entire fleet, and drag him to a watery grave. Him killing the moon spirit also makes this a Karmic Death. Especially ironic considering that his "The Reason You Suck" Speech to Zuko a few minutes before would fit perfectly considering the circumstances behind him killing the Moon Spirit.
Later there's Combustion Man, who twice tries to use his explosion powers after a nasty blow to the head. The first time it detonates prematurely, sending him flying back. The second time it doesn't even leave and blows him up.
Iroh's lightning redirection technique is basically a way to make this happen to someone. Zuko is the only one who uses it in a weaponized fashion, where Iroh and Aang (and actually Zuko too, once) use it to simply redirect the lightning off in a different direction.
The Grand Finale pulls this trope on Zuko himself with regards to this very strategy. When he tries to goad Azula into striking at him, she sees through this and aims her lightning at Katara instead, forcing him to take the blow for her. And in turn, to top it all off, she promptly gets her ass kicked by none other than Katara herself!
Ozai's Humiliation Conga in the final could be said to have started the moment he tried burning his son's face off and then banishing him. One Heel-Face Turn later means a full-actualised Avatar, thanks to learning true Firebending techniques. Added to that his own attempts to play with said Avatar like a cat with a mouse resulting in unblocking a chakra point... and... whoopsie.
Plankton's first appearance in SpongeBob SquarePants results in this. Having controlled SpongeBob mentally into delivering him a Krabby Patty, Plankton threatens to force him to drop it into a special analytical machine. However, after SpongeBob gives a mouth-watering 'eulogy', Plankton attempts to eat the Krabby Patty but falls into the machine instead.
In many of the early episodes, Squidward's suffering is caused by his own jerkish actions, such as in one episode where Squidward messes with messages Spongebob and Patrick send to trick them into thinking that they're no longer friends. This prompts Spongebob and Patrick to start looking for a new best friend, and they both choose Squidward, then get into a fight over who Squidward likes more, wrecking Squidward's life in the process. Later seasons scrapped this in favour of just making Spongebob and Patrick complete idiots who make life a living hell for everyone around them.
Squidward hasn't really learned a thing, as he still likes to mess with Spongebob.
A better Barbie example would be how Exact Words screws over the evil lady in her version of Rapunzel.
And Diamond Castle wasn't even the first time Barbie bounced back a spell to its caster: in her version of 12 Dancing Princesses, her Evil Stepmother has a wish-granting flower. Barbie has a fan. Figure it out.
The Trope was lampshaded in Celebrity Deathmatch. While the Trope certainly applies in several fights, and did indeed during the Chuck Berry/James Brown match, it elected this remark from Nick Diamond:
Nick: Hoist on his own petard? Well I don't think the audience knows what "petard" means. Cause I sure don't.
An interesting variant in Batman Beyond: Return of the Joker in that the Joker is killed by the same weapon he used on one of his own thugs in an earlier scene. What makes this interesting is that, while in order of appearance he shot the gun first, the scene where he dies chronologically happens some forty years before he actually killed the goon. Considering also that he was shot by Tim Drake, who was brutalized by Joker and used as a psychological weapon against Batman, he might have been hoisted on two petards at once.
And then, later, Joker - now residing in Tim Drake's body with the wonders of modern technology - is ended for good by his own electrical joy-buzzer.
More than that. Joker is undone by the new Batman (Terry McGinnis) using the same methods Joker always used to unnerve Bruce Wayne - jokes and insults. Turns out Joker can dish out but he can't take it.
In the series proper, Derek Powers gets infected by the very nerve gas that he was going to sell to a foreign dignitary. The attempt to save his life from said gas exposure only ends up turning him into Blight, a radioactive meltdown incarnate.
Also, even later, he ends up being backstabbed by his son, who was acting under the belief that he should backstab anyone he can for power, a belief that Derek Powers ironically taught him.
Paxton Powers, the above mentioned son, was later abducted by the Royal Flush Gang, who demanded ransom. Bruce Wayne said Wayne-Powers Enterprises wouldn't pay because it was against company policy and that Paxton would know since he wrote it.
Shriek is rendered deaf after his shockwave suit malfunctions, the drug dealer selling Venom slappers on the street dies(?) of an overdose after falling into a pile of them (and Bane himself was rendered a vegetable after a lifetime of using Venom), Dr. Cuvier's fate is sealed after he is injected with too much of his splicer formula, turning him into a walking pile of mutations...this happens a lot in the series.
Yet another example: in the episode "Sneak Peak," the villain wears a belt that makes him intangible. He uses it so much that it starts to alter his body and make him permanently intangible, After a desperate attempt to blackmail Batman for a cure fails, he ends up turning intangible for the final time and falls through the ground to the center of the Earth.
Syndrome in The Incredibles is knocked onto the wing of his jet and subsequently sucked into its engine. There's a long enough pause between the two that Syndrome easily could have survived had he not been wearing a cape — which the audience has been warned is a bad fashion choice for a superhero, or remembered one of his rocket boots was still working.
This happened a good deal to Syndrome. His robot was so smart that it figured out his wrist computer was a threat and shot it off. He was knocked into the engine by Mr. Incredible's sports car, that Syndrome had essentially paid for by hiring him for secret hero work. Also, this secret hero work helped Mr. Incredible bounce back from a flabby has-been who barely survived a prototype robot, into the efficient, superheroic persona of his glory days who could fight back. And his right-hand, Mirage, betrays him at the critical moment, largely due to his own cavalier attitude when Mr. Incredible was threatening to kill her.
"Mystery of the Lizard Men". The Big Bad fires a laser at the Quests' ship, Dr. Quest reflects it back with a mirror and blows him up.
"Arctic Splashdown". An enemy Mook tries to blow up the Quest's ship with a bomb. It ends up falling off the ship (thanks to Bandit), lands in the Mook's raft and blows him up.
"The Curse of Anubis". The Big Bad is killed by a cave-in while trying to trap the Quests inside a burial chamber. To be fair, the walking undead mummy who'd been after him for the whole episode and had finally caught him would most likely have killed him anyway.
"Dragons of Ashida". Dr. Ashida breeds huge carnivorous lizards that he uses to hunt down escaped servants (and eventually the Quests). At the end of the episode his servant Sumi finally has had enough of the doctor's abuse and throws him into the dragons' pit, where he's eaten alive.
"Pirates from Below". Villains try to blow up the Quests' underwater vehicle with a mine. Race Bannon removes it and releases it, whereupon it floats up to the bottom of the Big Bad's boat and goes "Boom".
"The Devil's Tower". Von Dueffel blows off his biplane's wing with a hand grenade he was attempting to throw at Dr. Quest and crashes.
"The Quetong Missile Mystery". General Fong shoots a guard out of pure frustration at the Quests escaping him. The dead guard then falls on a Plunger Detonator and blows Fong up with one of his own planted mines.
"House of Seven Gargoyles". Enemy Mooks shooting at Dr. Quest while they're under a glacier cause an ice collapse, killing them and the Big Bad as well.
"Terror Island". Dr. Chu Sing Ling is blown up by a power plant explosion caused by one of the giant monsters he created.
"The Riddle of the Gold". Ali plans to use a tiger to kill Dr. Quest, but the tiger ends up killing him instead.
Transformers Armada has a schemer by the name of Thrust. Sideways convinces the guy to side with giant, planet-eating Transformer Unicron. While everyone else is trying to defend their home planet from Unicron, Thrust is standing on the big guy's shoulder. Unicron starts to transform, and Thrust is knocked off balance and crushed in one of Unicron's joints.
To make it even more ironic, Thrust was in the middle of gloating to Galvatron (whom he'd betrayed) when this happened; he ended up begging Galvatron to help him, but Galvatron simply walked away, leaving him to his fate.
In the finale of the 1981 Spider-Man cartoon's Story Arc, Doctor Doom, who has finally taken over the world through clever use of a satellite-mounted laser, has his plot foiled and is subsequently vaporized by the same device.
In "Leave the Busting to Us", Doof escapes from Perry in the van he stole from the Bust 'Em people. He then mocks Perry for having to stop at the traffic light since he's a good guy, while as a villain he doesn't have to obey the rules... then is promptly caught up in the tornado accidentally created by his Gloominator 5000-Inator.
On Drawn Together, Clara shuts down Wooldoor Sockbat's "Clum Babies" store (Wooldor's sperm have magic healing powers) in a transparent parody of religious objections to stem-cell research. She contracts tuberculosis shortly thereafter.
Clara: Please! [cough] I don't want [cough] to die [cough] so ironically... [passes out]
The first occasion occurred in "Return to New York" with Baxter Stockman, where, after the main power source of his exo-suit is destroyed, he gets back up, again, and gloats about how each component of it has its own backup power supply, which prompts Donatello to work over to an arm-cannon that was cut off earlier and says "So what you're saying is, this arm should still be fully functioning right?" Cue hilarious Oh Crap! moment before Don blows away Stockmen with his own gun.
In the season 2 finale of The Spectacular Spider-Man, Green Goblin's glider is damaged after Spider-Man uses one of his own bombs against him, which then sends Goblin into a large container of more of his own bombs, originally intended to kill Spider-Man, creating a tremendous explosion. Unfortunately, Joker Immunity applies, because, of course, No One Could Survive That.
An earlier example would be Venom's return. Venom stole a genetic cleanser in order to strip Spidey of his powers, and then reveal his identity to the world, so he would be defenseless against all the enemies he made over the last few months. However, it was Spider-Man who used the cleanser to separate Eddie from Venom.
Said again in another episode by second generation Batman after The Joker is exposed to his own gas.
Batmite, in the final episode of the series, ends up falling due to his own scheme: the plan was to make the show jump the shark to the point that it would be cancelled, to make room for a new Batman show. He did get it cancelled... but failed to consider that, as a fictional character that is part of the show and too silly for most Batman adaptions, he would also vanish.
The Herculoids. Gorvak, the leader of "The Android People", is killed by the warrior android duplicate of Zandor he created.
In G.I. Joe: Resolute, Cobra Commander's last-ditch effort to get back at the Joe's is aiming his super weapon on Washington, and to ensure he survives he locks himself up in a saferoom. Duke then aims his WMD at his base and traps the Commander in his own saferoom. However, he somehow escapes.
In one episode, the narrator even said the phrase word for word. Clearly, this saying has been around for some time.
V.V. Argost gets this during the finale of The Secret Saturdays. After killing Zak's Mirror Universe counterpart and absorbing his powers, he proceeds to absorb Zak's powers as well. And here's where V.V. made his big mistake. Zak Monday was an anti-matter counterpart to Zak Saturday. And anti-matter and regular matter do not mix. Argost learns this the hard way when the combination atomizes him out of existence.
He actually gets a triple' dose of this because Zak tried to warn Argost about it but he couldn't hear him because he had to protect himself from the sound-based weapon he was using to absorb his powers in the first place. So not only did the mixing matter and anti-matter cause his death, the weapon he used to do it and what he was using to protect himself from it all lead to his demise.
In Justice League, Amazo has copied the powers of six of the seven Leaguers and is winning handily. Just as he's about to win, Martian Manhunter reveals himself and deliberately lets himself be copied so that Amazo can use telepathy to reveal Lex Luthor's true intentions. Once he realizes he was just a pawn in Luthor's latest scheme, Amazo leaves to explore the universe and find himself.
At the end of the episode "Only A Dream," Dr. Destiny falls on the syringe of mind-erasing drugs he intended to use on Batman, leaving himself a vegetable.
In the episode "Crippled Summer", Nathan's attempts to get rid of Jimmy backfire on him, thanks to his sidekick Mimsy.
In "Cartman Sucks", Cartman decides to show an incriminating photo to the class before Kyle can to take the wind out of his sales, only to discover that Kyle didn't have it after all and that he simply misplaced it.
While he almost always walks away from it, this seems to happen to ReBoot's Megabyte quite often.
Megabyte steals a supposed weapon from Hexadecimal, which turns out to be a viral bug that freezes whatever it comes in contact with, starting with him.
His attempts to leech energy from games backfires when he gets stuck within two games merged together and attacked by the resulting game characters.
Attempting to steal Mainframe's core energy gets him knocked into said energy and becoming part of a game which would destroy the entire system if lost.
Doublecrossing Mouse more than once turns out to be more than a mistake when she reconfigures his portal to the Supercomputer to one leading to the Web.
Then there's turning Hexadecimal into a weapon, which, once she gets free, gets his Tor wrecked.
In Transformers Animated Optimus beats Soundwave to scrap, using Soundwave's own electric guitar, Laserbeak.
In the Family Guy episode "Padre de Familia", Peter demanded that the brewery where he works fire all illegal immigrants. Soon, he found out that he himself is an illegal immigrant. Three guesses what happens next. Although this is only an example because the writers evidently have no idea what an illegal immigrant is.
A heartbreaking one comes from the episode "Life of Brian". Stewie decides that his time machine is just too much trouble and destroys it. A few moments later, an out of control driver strikes Brian while he was setting up for street hockey, killing him. After awhile, Stewie realizes that he can undo Brian's death and seeks to repair his time machine. However, he finds out that he can't obtain a crucial piece because the man who he obtained it from was killed for unknowingly drawing Mohammad.
Discord from My Little Pony: Friendship Is Magic is ultimately defeated thanks to quite a few of his own petards. First, he let the mane cast get back the Elements Of Harmony and letting them try to hit him with them, which he'd ensured wouldn't work since he'd broken apart their friendship, in order to crush any hope they had left. Unfortunately for him, Twilight Sparkle figures out how to break his Mind Rape on the rest of the gang and they confront him with their friendship, and the Elements Of Harmony, renewed. Applejack mentions this, but Discord, having turned her into a liar and not knowing she's turned back, doesn't listen to her. He refuses to believe his Mind Rape had been undone and thus tries to repeat what he did before, only to be done in by his own Genre Savvy. It's impossible to tell whether or not the Elements Of Harmony will fizzle out until they're just about to fire, rendering Discord incapable of realizing his folly until it's too late.
Queen Chrysalis, the leader of the Changelings and Big Bad of the season 2 finale, is revealed to have been feeding off of Shining Armor's love for Cadence to make herself stronger. When Shining is broken free of her control, he and Cadence use the realPower of Love to send her and her mooks flying off into the distance Team Rocket style.
In the very first episode, Nightmare Moon's attempts to stop the mane cast from getting to the Elements of Harmony not only leads to Twilight realizing that she and the others represent each of the Elements of Harmony, but also allows her to befriend the others and actually be able to use the elements.
In Dial M For Monkey a villain obsessed with gold ends up being melted underneath a pile of gold bars.
Rugrats: If Angelica does something to the babies or tries to get something for herself, chances are that what she did will turn around and bite her in the ass. These have included revealing she broke Tommy's lamp (and forgetting that the grown ups can hear her), handcuffing herself to her bed, and wiping out on the ball that she had earlier tossed over the fence.
On the non-Angelica side of things, there's the Junk Food Kid, a toddler bully who was beaten when Tommy burst the humongous bubble gum bubble using a candy cane she tossed aside.
This is how Airachnid got Put on a Bus. Arcee tricked her into getting frozen in a stasis pod formerly occupied by one of her Insecticon minions.
The ultimate goal of Krytus, from Hot Wheels Battle Force 5, is to free the locked away Red Sentient civilization, so they can have their revenge on the Blues. When he accomplishes this goal, he finds out the Reds are just as sick of the war as the Blues, and they promptly seal Krytus away.
American Dad!: "People always forget the mic is on," according to Steve. Later, he, too, forgets the mic is on. Later still, Snot does, too.
In the first half of the season 1 finale of Ninjago, Big Bad Pythor P. Chumsworth succeeds in using the four Silver Fang Blades to awaken the Great Devourer. Not only did he underestimate the Devourer's size, (he thought it was inside the statue that he put the Fang Blades in when it was actually in an underground chamber due to being so huge) he also didn't consider it not obeying him, resulting in him being one of its only two victims.
The Great Devourer itself deserves a mention because it was ultimately destroyed by Lord Garmadon, who became what he is now because it bit him as a child.
In "The Clock King", Batman uses the tape Fugate left him to escape his Death Trap. In Time out of joint, Batman uses the same time-slowing device Fugate stole to stop him.
The Scarecrow fell victim to his own fear serum in two separate episodes. (After the second time, he apparently learned to be more careful.)
In an episode of T.U.F.F. Puppy Bird Brain discovers that he's the Last of His Kind, meaning that he's an endangered species and can now go about his business unimpeded because Dudley and Kitty legally can't hurt him. At the end of the episode he makes a mutant clone of himself, meaning he's no longer the last member of his species and they can hurt him again.
Near the end of the Ed, Edd n Eddy episode "Sir Ed-A-Lot", Eddy locks Sarah in a "cage" just like she did to him earlier.
In one episode of Animaniacs, disgraced cartoon character Buddy attempts to get revenge on the Warner Siblings for ousting him of his (incredibly boring) cartoons by blowing them up at a party held in their honor. However, when Yakko admits they wouldn't have gotten there without Buddy, he races out to accept an award only to realize too late he fell for another one of their gags and is taken out by his own bomb, then is blasted into the surface of a giant prop mallet, which then falls onto the stage, crushing him.
In the finale of Total Drama Revenge of the Island, Cameron attempts to defeat Lightning in a duel by using his Powered Armor to magnetize the latter's junk armor. He succeeds, causing Lightning's armor to attract several oil drums that promptly explode when Lightning's club becomes a lightning rod, but Cameron's armor becomes completely drained and he falls over first, so Lightning, albeit burnt and dizzied by the explosion, falls on him and wins.
At the climax of the first vignette of Kronk's New Groove, Yzma uses her failsafe plan to escape the mob of angry elderly folk whom she cheated by drinking a potion to transform into a ridiculously adorable bunny, simultaneously placating the angry mob, and attracting the attention of a mother eagle. The last we see of bunny!Yzma is her screaming just as the eagle's two ravenous chicks are about to pounce on her.
Speaking of Yzma, in The Emperor's New Groove, had she not sent Kronk down a trapdoor, he would have (accidentally) stopped kitten!Yzma from drinking the antidote potion.
Wunschpunsch: Has anyone kept counting how many spells of the week have somehow brought harm to the wizards or at least one of them?
Code Lyoko: XANA having the Mantas attack and possibly kill Franz Hopper is what convinces Aelita to use the last of Franz' energy to activate the multi-agent program. But with XANA's return, it seems to have been just another part of its ironically named Xanatos Gambit, albeit one that seemed to be a major setback.
In one episode of Doug, Doug is caught with Mr. Bone's yodeling trophy and he has no way of trying to prove he didn't have it nor proving he was framed. Stuck with detention, he finds himself being confronted by Roger, who reveals that he was the one who did it and, as he gloats, accidentally pushes the PA system, having his confession echoed throughout the school. Needless to say, Roger went into panic mode once Mr. Bone confronted him.
In an episode of The Mask, the titular character uses a time-manipulating villain's own time-loop device against her, trapping her in an endless cycle of him dropping a grandfather clock over her head.
Much like Wile E. Coyote, Dick Dastardly falls victim to his own machinations in trying top the other Wacky Racers.
The Dexter's Laboratory movie "Ego Trip" shows that Mandark would be ultimately defeated and rendered harmless by his own handiwork: Mandark devises a machine that steals all of humanity's intelligence using a power source Dexter created years earlier, turning him into a large (as in fat) emperor. However, during a fight between four eras of Dexters and Mandarks, the modern day Dee-Dee wanders in, pulls her What Does This Button Do? routine and deactivates the machine, restoring humanity's lost IQ and causing Mandark's body to explode, leaving him a helpless brain.
"The Continuum Of Cartoon Fools" has Dexter blocking all the entrances to his lab in order to keep Dee Dee out, only to lock himself out in the process as well.
In "Trapped With A Vengeance", Yonni The Yanitor builds a death course as a mans of revenge against Dexter for making a mess in his school. At the end, Yonni causes a mess anyway and gets a scolding from his wife, thinking that he was goofing off.
The New Adventures of Superman. In the episode "The Electro-Magnetic Monster", Superman uses the Deimosians' own electromagnetic device against their ship to defeat them.
The Simpsons does this to Sideshow Bob in one episode, with the phrase "Hoist on his own petard" being part of his plan for extra humor. Basically, Sideshow Bob creates a fake restaurant designed specifically to appeal to the Simpsons family. When they come over, Sideshow Bob ties them up next to a crate of dynamite that has a laptop computer on top. The computer's battery will overheat, detonating the dynamite. Sideshow Bob drops the trope's name, but gets it wrong, causing him to go look it up on Wikipedia and getting him blown up by his own trap.
A non fatal example in Adventure Time: Flame Princess tricks Ice King into hurting himself with his own freeze attack by throwing a fireball above his head, which he then freezes, causing the block of ice to land on his head.
In Kung Fu Panda Legendsof Awesomeness, the now mentally unstable General Tsin (who at that point have been capturing the show's villains and paralyzing them with a smoke that left them completely immobile, yet conscious and aware) actually says this word for word when he suggests that Po would use the same gas he used on his recently freed enemies to paralyze him. Luckily, Po has other ideas:
Tsin: So what are you gonna do now? Freeze me like I did them?! Hoist me with my own petard?! Po: Don't have a...petard handy, but aahhh I do have another idea.
(cut to Chorh-Gom prison where Tsin is put behind bars)
Footrot Flats: The Dog's Tale: During the rugby game, Wal throws an uppercut in the scrum... and punches himself. To add insult to injury, the referee tells him that next time he punches himself, he'll be sent off.
In King of the Hill, Buck Strickland's mistress Debbie Grund plans to kill Buck after he spurned her for his wife, intending to pop out of a dumpster and shoot him after he went to a nearby motel. Buck wasn't able to get there on time due to circumstance and took so long that Debbie got hungry and went to the nearby restaurant to get some food. On the way back she had too much trouble balancing her nachos and shotgun at the same time so she threw the shotgun into the dumpster and promptly shot herself dead climbing in.