(The heroes' submarine is grabbed by a huge Opee Sea Killer) Jar Jar: Big Gooba fish!!!! HUGE TEETH!!!! (The Opee Sea Killer is grabbed by the much larger Sando Aqua Monster) Qui-Gon Jinn: There's always a bigger fish.
A McDonald's ad shows a kid using french fries as bait while fishing. Soon a fish bites...and a bigger one...and an even bigger one...which ends with a long chain of fish, ending with a huge sperm whale.
Anime & Manga
In Monster, Nina is saved from Professor Geidlitz by Johan. What makes this better is that they were using her as bait to lure Johan in to convince him to lead their group and make "the master race" dominant once again, seeing him as the next Hitler. Anna tried to warn them that Johan didn't care about their cause or any cause. They discover too late that she's correct.
Also happens in the manga. One example being after the Fishman Island arc, where a fish the crew catches is then eaten by a bigger fish, which is eaten by an even bigger fish, which is then killed by Zoro.
A heroic variant in the Rurouni Kenshin episode, "Birth of a Child Swordsman": Yahiko is being chased by the gang of thugs he's been dealing with the entire episode. He leads them into an narrow alleyway where he can fight them one-on-one, but the thugs wise up and approach en masse, knives drawn. Then the thugs look up and notice Kenshin and Sanosuke on the wall behind Yahiko (either of whom would've been enough to make the thugs pause). Most of the thugs flee, but the leader wants to settle the score with Yahiko. He ends up giving Yahiko his first victory in a real fight.
In the finale Kriemhild Gretchen is defeated by Madoka via a Wishplosion.
Dragon Ball Z: Frieza and his even stronger father are coming. This could mean the end of all life on Earth. As soon as they arrive, a person we've never seen before shows up and cuts them both in half with a sword.
To elaborate when the show started, Raditz was the most powerful character. He was killed by Piccolo who was himself killed by Nappa who was then killed by Vegeta who was himself killed by Frieza who as previously mentioned was killed by Future Trunks who was later killed by Cell who was killed by Gohan who was killed by Majin Buu who was killed by Goku. Wow.
Extremely prominent in Toriko, where high level predatory monsters will be dined upon by even higher level ones. Case in point, recently when the Four Beasts awoke from their centuries old slumber to invade the human world, one of them killed a Regal Mammoth with one attack. In earlier chapters, said Regal Mammoth was probably the largest creature seen in the series so far (being approximately one kilometer in height), and had the ability to inhale hundreds of smaller beasts through one of its two trunks and spitting bones out the other.
In the Pokémon episode "Attack of the Prehistoric Pokemon", Ash, Pikachu, and Team Rocket are stuck underground with some recently-awoken and very grumpy Omanytes, Omastars, Kabuto, and Kabutops. After some back-and-forth battling, the ancient Pokemon have them on the ropes when they suddenly look around in a panic and flee. Ash wonders why they're running. CueAerodactyl.
The climax of Bone is an interesting double-helping of this trope: the dragon-goddess Mim's roaring rampage is set to wipe most of the heroes (most of the planet) off the map. Meanwhile, Thorn and Fone Bone are being pursued by the rest of the dragons, in a blind rage. The dragons pursue Thorn and Fone to the surface, at which point they see Mim, and they break off their pursuit to go calm their queen down.
In an early Sunday strip of Calvin and Hobbes, Calvin shrinks down suddenly to the size of a bug from the perspective of other bugs. A fly tries to step on him until a frog eats it.
One Sherman's Lagoon comic has a progression of Bigger Fish eating each other. When Sherman, a Great White Shark, shows up to eat the third, another fish protests, "You're going out of turn. I eat that guy, then you eat me."
Occurs in Nth Man: The Ultimate Ninja when Reality Warper Alfie O'Meagan is waiting for a cosmic being called M'Gubgub. He barely avoids being stepped on by a massive alien who dwarfs the planet and proceeds to praise M'Gubgub... only for the alien to run away in a panic, as the galaxy-dwarfing M'Gubgub arrives.
This◊ strip by Argentinian cartoonist Quino (the text translates as "Death to the big guy"). Also this one◊.
In one Doctor Strange story arc, Strange is menaced by the cosmically powerful sorceress Umar. He finds and releases an artificial Eldritch Abomination called Zom which is the one thing that scares her. Needless to say this quickly backfires (if Strange couldn't handle Umar, he has no chance of containing something bigger than her), and he has to find a bigger fish yet, going through a chain of deals which ends with the Living Tribunal, the single biggest fish in the entire Marvel Multiverse (apart from an unseen, vaguely-defined "One-Above-All").
The Tribunal himself was apparently defeated in the leadup to Infinity. What did it is unknown at present. Has he finally found his own Bigger Fish?
It seems this was done by the mysterious 'Rabum Alal' - Sumerian (yes, really) for "Great Destroyer" - as Black Swan, kind of his herald in a sense, calls him.
Staggeringly, even Darkseid has a Bigger Fish - his own father, Yuga Khan. Thankfully for Darkseid and the universe, all he cares about is learning the truth about the Source, and was trapped, as everybody else is, attempting to penetrate it. However, when he freed himself, he briefly terrorized Apokolips even worse than his son did, and caused Darkseid to attempt to hide. Having learned nothing from his previous attempt, Yuga Khan once again attempted to invade the Source and ended up once again trapped.
In Game Theory, Nanoha and Fate are outmatched by one of the Jewel Seed monsters until Zest makes his appearance by killing it in one blow.
In A Dream Of Dawn, Nightmare Moon has overthrown Celestia, shattered the Elements of Harmony and rules Equestria with an iron hoof. Her reign lasts about five minutes after Discord returns.
Films — Animation
Humorously meddled with in The SpongeBob SquarePants Movie when Dennis the Bounty Hunter finally catches up to SpongeBob and Patrick. Dennis goes to step on SpongeBob and Patrick, only to be stomped on by the "Cyclops". Patrick even yells out "Bigger Boot!"
Played straight earlier in the film when the frogfish that ate their car is itself eaten by an enormous deep-sea eel. SpongeBob and Patrick's shocked expressions◊ are priceless, to the point of becoming a meme - at least, Patrick did.
In Help! I'm a Fish, the main characters are collecting ingredients to make a potion to turn them back into humans, but run into trouble getting an octopus to squirt ink, as it is much bigger than they are and thus just grabs them. It does eventually squirt ink and swim away, which Fly attributes to their screaming scaring it off, but was really because of the great white shark approaching...
In the "Mickey and the Beanstalk" segment of Fun and Fancy Free, when Mickey Mouse, Donald Duck, and Goofy arrive at Willie the Giant's castle after their house is carried upwards by a beanstalk, a giant dragonfly swoops down and tries to attack the three, but a giant catfish living in Willie's moat jumps up and eats the dragonfly.
Films — Live-Action
In Star WarsThe Phantom Menace, as Qui-Gon, Obi-Wan and Jar Jar travel in a sub through the watery core of Naboo, this happens twice in a row for a total of 4 progressively bigger fish. (Although the 2nd and 4th monsters are the same individual.)
The heroes of Jurassic Park are about to get eaten by velociraptors, but the T. rex shows up to save the day.
In Jurassic Park III, the heroes run from a Spinosaurus straight into the hunting grounds of a T.Rex. The spinosaur "rescues" the heroes by killing the T. rex, but later begins chasing them again.
Or you could see this as a kind of subversion. The T. rex seems like it might pull off a "bigger fish" moment, but the scene quickly turns into an example of The Worf Effect or Make Way For The New Villains instead. T. rex had its badass cred established in the previous two movies, so the Spinosaurus pulling off a Curbstomp Battle against it demonstrates just how dangerous this unfamiliar dinosaur is.
In Peter Jackson's King Kong, the heroine hides from a huge carnivorous lizard in a hollow log, and it tears at the wood to try to get her. Suddenly it stops, and she seems safe... until half the same lizard is seen dangling from the jaws of a ginormous V. rex, which just bit it in two. Kong himself is a near constant example of this trope in the first half of the movie, as he repeatedly kills a number of animals that are trying to eat Anne Darrow.
In Avatar, Jake faces down a huge, charging rhino-like titanothere. When it stops and retreats, he thinks he's won, only to have to run from what really scared it off: the bigger and nastier-looking carnivorous thanator that was creeping up behind him.
Played straight in Godzilla vs. Mechagodzilla II. Several members of the JSDF are attacked by Rodan as they try to take an egg from a nest. And, then, Godzilla (who is larger than Rodan) shows up and attacks both the JSDF and Rodan.
Averted in the film Godzilla, Mothra, King Ghidorah: Giant Monsters All-Out Attack!. Actually Baragon is never attacked by the JDSF, as the Cabinet never actually takes action. In this instance Godzilla is still the Bigger Fish. Baragon goes straight to battle with him. Baragon is the hero, but nowhere near being the bigger fish.
This is the main dynamic between Godzilla and the other monsters in Godzilla (2014). The 2013 Comic-Con trailer especially made a point of illustrating this: the centerpiece scene shows one of the monsters, which io9 compared to the Cloverfield monster in terms of both size and appearance, wrecking an airport. It's a big, scary creature compared to the puny humans — and then the scene culminates in a shot of the monster being dwarfed by Godzilla's foot.
Subverted in The Colour of Magic, where a sinking pirate ship is devoured by a sea monster the size of a village... which shortly washes up dead on an island, as the smaller fish it swallowed along with the ship just happened to be the Luggage. Which kicked it to death from the inside.
In Lake Placid, the protagonists are arguing near the lakeside when a bear appears and attacks them. Then the crocodile unexpectedly pops out of the water and drags the bear in by its leg.
In the beginning of Sharktopus, a beach girl is attacked by a shark while swimming off the shoreline, but the Sharktopus saves her by devouring it.
In Two Serpents Rise, the Caleb woke the King in Red to curb-stomp high priest Temoc when the fanatic tried to sacrifice his best friend.
Flipped on its head by Jonathan Swift:
So nat'ralists observe, a flea Hath smaller fleas that on him prey, And these have smaller fleas that bite 'em, And so proceed ad infinitum.
In Watership Down, after Hazel and Co. are attacked by General Woundwort, a massive dog is led into General Woundwort's forces, who naturally run. General Woundwort himself stays to beat up the dog. It’s worth noting that most of the characters are non-anthropomorphic rabbits, with the exception of Kehaar the seagull.
Well, they wouldn't, would they? Bigger Fish are often Hungrier Fish also.
Subverted in Tuf Voyaging. Wild Card Rica Dawnstar has Tuf outgunned and at her mercy, and refuses to believe him when he tries to point out the T. rex creeping up behind her. It looks like this trope will kick in...then it turns out she was toying with Tuf, and had the Phlebotinium to control the T. rex all along.
In Cain's Last Stand, the schola and PDF are completely swamped by the forces of Chaos. They've fallen back to the secret facility containing the Shadowlight, and are about to be overwhelmed when the Necrons decide to show up. They butcher the forces of Chaos pretty handily, giving Ciaphas Cain note HERO OF THE IMPERIUM!!! and company an opportunity to evacuate.
Alan Dean Foster loves this trope, especially as an excuse to show off his weird alien ecologies.
In Drowning World, characters menaced by a branch-clambering maccaluca are saved when it's snapped up by a vuniwai leaping up from the water.
Mid-Flinx is essentially one long string of Bigger Fish: Flinx's initial human pursuers are killed and supplanted by AAnn pursuers, and both groups of enemies are gradually picked off by one bizarre jungle predator after another.
It's played with in For Love Of Mother-Not when the penestral (roughly speaking, a pike that's 50 feet long) that attacks the bad guys doesn't save the heroes from them (it eats their boat, but the real villains has just escaped onto a flyer). The fisherwoman escorting Flinx scoffs at its size, pointing out that it wasn't terribly big for a penestral, and that the penestral is only a mid-range predator anyway. She offers to take Flinx fishing for oboweir sometime, and when he asks the inevitable "What's an oboweir?", her reply is "A fish that eats penestral."
In Casino Royale (book and movie), Bond is rescued from Le Chiffre when Le Chiffre's own superiors (SMERSH or QUANTUM, depending on the source) assassinate him.
Bond himself is the Bigger Fish in The Spy Who Loved Me (the original novel onlynote Ian Fleming was very dissatisfied with this novel and only gave permission for the title to be used when he sold the film rights. Thus, the film has very little similarity to the novel.) when, while checking into a hotel, he walks in on two small-time mobsters who are attempting to rape Viv Michel.
A couple of times in The Dresden Files. In Proven Guilty, Harry has just escaped from where Madrigal Raith and his lackey have been holding him hostage and they've started fighting... Only for the bad guys to end up running away as fast as possible when the book's actual Big Bad shows up. Small Favor also has a sequence where Harry's trying to get away from a Fallen Angel, only for Bad Ass fairy assassin Eldest Brother Gruff to show up and take out the guy without even trying.
Used in Nightingale's Lament, when a limo Taylor is riding in is about to be attacked by a predator camouflaged as another car. Before it can do any damage, the critter is picked up and carried off by something HUGE with talons and wings. Possibly a subversion, as the limo might've been able to hold off the car-mimicking monster with its built-in defenses.
In the 11th book of A Series of Unfortunate Events, the Baudelaire orphans are in a submarine which is being attacked by the main villain. However, when a mysterious question mark appears on the radar, everyone is scared, including the attackers. To make matters worse/better, the author never says just what the question mark was.
Once he tried to feed all the animals in all the world in one day, but when the food was ready an Animal came out of the deep sea and ate it up in three mouthfuls. Suleiman-bin-Daoud was very surprised and said, "O Animal, who are you?" And the Animal said, "O King, live for ever! I am the smallest of thirty thousand brothers, and our home is at the bottom of the sea. We heard that you were going to feed all the animals in all the world, and my brothers sent me to ask when dinner would be ready."
The Empire plays this role at the end of Shadows of the Empire, just as it looks like the rebels are about to be obliterated by Xizor's forces.
In Harry Potter and the Order of the Phoenix, Harry and Hermione are surrounded by an angry mob of centaurs. Just as the situation is looking rather grim, a giant shows up, scattering the herd and chasing them into the forest. Hermione, characteristically, is worried about the centaurs.... It's worth noting that these centaurs, in turn, had gotten rid of Delores Umbridge, the Faux Affably Evil, ultra-feminine Defense Against the Dark Arts professor.
In Peter Benchley's "Beast", the titular giant squid is moments from finishing the remaining characters when it is attacked, killed, and presumably eaten by an equally massive sperm whale.
In 100 Great Science Fiction Short Short Stories, there's a story by Martin Gardner called "Thang," in which the titular being started eating the solar system but was interrupted by an even larger being scooping him up and swallowing him. "For there are other gods than Thang."
In the third book of Robin Hobb's Liveship Traders trilogy, Bingtown, the town in which much of the action takes place, is being completely overrun by the Chalcedonians... when the last of the ancient race of dragons wakes from her unexpectedly lengthy slumber, and goes looking in Bingtown for those responsible for her awakening. The Chalcedonians fire arrows at her in terror, and in response, she effortlessly kills them all.
LOST season 4 is all over this trope. One group of Losties hides from the freighties in the Others' Barracks. Later, a group cornered in a house are able to leave because the smoke monster (the series' original antagonist) attacks the bad guys. In the finale, when the Others showed up, fans at TWoP commented that they felt like the cavalry had arrived, quite a sharp contrast to the Others' first appearance in "Exodus Part 2".
Primeval Episode 6 features a scene in which Nick is rescued from a Future Predator when said predator is attacked by a Gorgonopsid.
Episode 3 features Nick being attacked by a mosasaur, only to have said mosasaur eaten by an even larger mosasaur right before it's about to chomp down on him.
One of the animation segues in an episode of Monty Python's Flying Circus has a section involving people being squashed on the streets by "killer cars", which were destroyed by a gigantic building-swallowing Siamese Cat, which was then killed by a several-hundred-foot-tall disembodied hand... and then it transitions into something else completely different.
Bored to Death: Our protagonist is saved from a scary murderous thug by driving into the back of a police car. While high.
The MST3k episode King Dinosaur features two astronauts trapped in a cave by a Tyrannosaurus rex that is actually an iguana. The arrival of a baby alligator with a fin glued on its back, and the ensuing "dinosaur" battle, allows them to make their getaway.
On Justified Boyd Crowder has just been 'arrested' by a mob hitman pretending to be a sheriff's deputy and is about to be taken to his death. US Marshall Raylan Givens wants to talk to Boyd about a related matter and is not amused when the 'deputy' gives him lip. The hitman draws his gun and Raylan shoots him dead. Later in the episode Boyd uses Summon Bigger Fish and asks the Detroit mob to help him deal with some corrupt local businessmen who made him An Offer You Can't Refuse. Later he notes that there are only two fish bigger than the Detroit mob: God and Uncle Sam. If Boyd gets on the bad side of the Detroit Don Theo Tonnin, he is screwed unless Raylan and the Marshalls take out Theo for him.
In Person of Interest, whenever there's a story arc about a villain containing elements of conspiracy, there seems to almost always be a more powerful, more mysterious bad guy behind them.
In Doctor Who, the "Predator of the Daleks" is one of the names for the Doctor, given to him by the Daleks themselves.
I know an old lady who swallowed a fly... and an increasing sequence of critters each swallowed to catch the previous one.
Pink Floyd's "The Wall": When we grew up and went to school / There were certain teachers who would / Hurt the children in any way they could ... But in the town, it was well known / When they got home at night, their fat and Psychopathic wives would thrash them / Within inches of their lives.
While GordonFreeman doesn't exactly need the help, there are numerous places in the Half-Life series where members of different factions fight and kill each other, effectively clearing Freeman's path (Marines and Xen aliens in Half-Life, Combine, Antlions and Headcrab Zombies in Half-Life 2 and its Episodes). Closer to the trope, this leads to at least two instances where a rampaging Antlion Guard slaughters a squad of Combine soldiers.
This trope is the major point of Feeding Frenzy. Eat small fish, become large fish, and avoid the even larger fish while doing that. Most levels have non-edible fish (which means, they eat you), or something else capable of killing you (mines or birds, or both!) but in several levels you get to be top dog of the seas.
No matter what fish you are in Odell Down Under, there is always something that can eat you. Even the largest fish, the great white shark, can still be eaten... by another great white shark.
In God of War: Chains of Olympus, Kratos fights a Cyclops, which is then eaten by a basilisk.
In AdventureQuest when you do the "Big Trouble in Little Granemor" quest you're attacked by a Giant Hungry Zombie after fighting off some vampires. The zombie makes about one attack before a Ribber randomly comes up and drags it away (with its mouth).
Spore features this trope quite prominently, particularly in the Cell Stage. If you happen to be in the middle of being attacked by a large organism, once in a while a larger creature comes along and scares off or eats your attacker.
It can happen in-game, too: dragons can randomly attack while the player is fighting off weaker enemies.
The Dragonborn themself is one. According to lore, Akatosh bestowed upon mortals the gift of Dragons-blood so that they may serve as guardians of mankind and as natural predators to Dragonkind. Indeed, part of what makes the Dragonborn so greatly feared is their ability to simply show up in the middle of a Dragon-attack, tear them apart, devour their very soul... and then promptly go on their way. There's a reason the Dragonborn is referred to in-universe as "The One They Fear".
Musashi Samurai Legend had a literal example with the Crimson Gorger. After the fight, it's about to eat Musashi, it then gets eaten by the Great Crimson Gorger, who then proceeds to continue the chase and therefore the boss fight.
BioShock uses this trope early on to introduce the Little Sister and Big Daddies. After injecting himself with the Electro Bolt plasmid, Jack is left nearly unconscious as two splicers poke his body, searching for Adam. They are scared off by the approaching footsteps of a big daddy.
Later on, Jack witnesses a scene where a splicer tries to harvest a Little Sister that's supposedly all alone, only for her scream to alert a Big Daddy that proceeds to beat the ever-loving crud out of the unlucky splicer.
In Aria of Sorrow, when you enter one boss fight room, a large number of smaller bats immediately form into a giant bat… Which then gets crushed by a giant hand belonging to Balore, the boss you actually end up fighting.
In Castlevania: Harmony of Dissonance where the Talos (the massive suit of armor that chases you in the beginning of the game) crushes a smaller Living Armor that is set up to be the boss.
In the KateModern episode "Answers", Michelle Clore orders her Shadow to carry off Lauren. As he is doing so, Terrence arrives and beats the Shadow in the face repeatedly with a golf club, apparently just for the hell of it. Lauren escapes.
In "Love on the 436", Terrence advances on the K-Team, only to get beaten up by the Shadow.
In a much earlier and more humorous example, Torg is about to be kissed by the ugliest woman in the world, but she is suddenly eaten by the alien that followed him from another dimension. She (the alien this time) seems about to eat him too, but he's still relieved.
In one episode of Black Dynamite the titular hero is on an island lost to time similar to King Kong's when he's attacked by a giant white wolf. He pulls his weapon but waits until the wolf is eaten by a bigger raptor. Then waits for the raptor to be eaten by a giant spider before finally taking said spider down with a single bullet. Now THAT is how you conserve ammo.
In the fourth episode of Avatar: The Last Airbender , Aang stops at Kyoshi Island to ride the elephant koi, koi-like fish at least 15 metres long. Later, we meet the Unagi, the sea serpent that eats them.
In the first episode of the third season, a giant serpent attacks the ship of the group, and then goes after the enemy ship that was attacking them, after a Tempting Fate phrase by Sokka.
In several classic Warner Bros. & MGM cartoons, one throwaway gag would be for a fish to eat something, then a bigger fish would eat that fish, then a bigger fish would eat that fish, then a punch line to the bit. Parodied on The Simpsons, where the 3-eyed fish is eaten by a 6-eyed fish, which is then eaten by a 9-eyed fish. Which is then eaten by a swimming Homer.
Parodied even earlier by Felix the Cat in "Neptune Nonsense": When the goldfish Felix was trying to catch has this happen to it, Felix manages to free the goldfish, only for it to turn around and eat all four fish that ate it. Felix quickly decides to find another fish.
In the Family Guy episode "Lois Kills Stewie", Lois describes via flashback that she took a job at a fat camp. At one point she has to take one of the campers out of another camper's mouth ('cause he's fat see, so he'd want to eat whatever he could), and then she has to pull another camper out of the mouth of the camper she'd just rescued.
There's always the classic gag from Looney Tunes, in which Granny picks up the dog and hits it until it spits out Sylvester, only to then pick up Sylvester and hit him until he spits out Tweety.
Wild Kratts: This happens no fewer than two times in quick succession in an almost Xanatos-like way. A giant squid and a mama sperm whale are battling it out over the baby sperm whale, when a net comes out of nowhere and takes Mama out of the fight. So Big Daddy Sperm Whale shows up and promptly makes calamari of the squid. Enter colossal squid.
Played with in an episode of The Angry Beavers where Norbert is admiring a rare fish in the river where their dam is. The fish is promptly eaten by a larger fish, which is eaten by another. This continues until the largest fish is eaten by a fish that was even smaller than the first one. Then that one is eaten by a orca whale. That episode centered all around the orca/killer whale Daggit brought to their pond after seeing it perform at a water theme park. It eventually started eating everything and everyONE, including the beavers. They were saved by a T-rex that happens to eat it... and this one too was brought home by Daggit, ready to eat them in the whale's place.
The Transformers Generation One episode "Child's Play" begins In Medias Res as the Decepticons capture a bunch of humans and treat them like toys before the Autobots arrive to save the day. Then, both sides end up on a planet where the inhabitants are so huge that Transformers are like toys to them.
At the end of the Wander Over Yonder episode "The Egg", a dragon-like creature tries to eat the newborn Bug-monster . . . until its much larger mother scares him off.
One amusing sequence in Wakfu has the girls falling into a swamp and being subjected to this repeatedly. First they run from a huge monster. Then they and the monster start running in the opposite direction from a bigger feline monster. Then all of them start running from an even bigger dinosaur. The dinosaur is puzzled when its prey suddenly run past it...only to get crushed underfoot by a much bigger dinosaur.
Invoking this trope is one of the most favourite attacks against "First Cause" arguments: Atheist, Agnostic or similar Skeptic: If God created us then who created God? And why does it have to be just God?
Subverted by Anselm's Ontological Argument, which is a logical attempt to prove the existence of God. Its main premise is that if God, i.e., an all-powerful being, did not exist at some point, then there would have to be a bigger "fish" to bring Him into existence, and then He would not be all-powerful, and therefore not God. According to Anselm, something which exists is 'greater' than something which doesn't exist. Since we can conceive of God existing and not existing, and the existing one is 'greater', then God must exist since he is the 'greatest' possible being we can conceive.
The food chain (or more accurately, the food web).
However, fictional depictions often do it wrong by having the bigger fish be not that much bigger than the one it takes out. In real life, a predator will rarely attack another predator that's close to its own size. Because even if it's successful, the odds of getting injured are high, and animals in the wild don't exactly have medics on hand to treat their injuries. Thus, hunting something that can put up a credible fight is high risk for low reward.
Pack predators may bring down larger prey with some frequency. In addition, there are rarely more than two or three levels of predation before reaching an apex predator. Each time a thing is eaten (a change in trophic level), there is usually a loss of at least 90% of the caloric energy from one level to another. In the simple chain grass - herbivorous insect - small bird - falcon, there were probably 1,000 calories worth of grass for every 1 calorie of falcon at the end. Food webs rarely have long, long chains of predation.
Jared Diamond once said: the reason nobody domesticates big predatory animals is the inefficiency of raising them - it takes a few tonnes of grass and grain to raise a cow, but it takes a lot of cows to raise a lion, while each cow needs grain and grass to be raised itself. Each pound of meat from a lion would be so expensive in terms of calories that nobody could afford to eat it regularly.
Food chains on land tend to be simple, but oceanic chains normally have many, many links because they start out with microscopic phytoplankton. So this is more likely to apply to fish than to land creatures.
There is a Permian fossil of a shark that ate an amphibian that had eaten a fish.
In 2009 off the eastern seaboard of Australia, a three metre (ten feet) great white shark was found entangled in shark nets. The nets hadn't killed the shark, in fact, the shark had been bitten clean in half by something twice as large. Only in Australia, folks.
If you're wondering what could have done that: Another Great White, a Saltwater Crocodile, or an Orca.
Point of order: The shark was still alive when it was hauled out of the water. Great whites are amazingly tough to survive a wound like that.
Speaking of Orcas, they are almost the perfect example of this trope in real life. Nigh-universally feared by people, the mighty great white shark is little more than prey for the even bigger and stronger Orca.
Proponents of globalization and similar trends point to this as a way to ensure world peace. The bigger fish in this case is economics. If two or more countries are intimately tied together economically, then they can't attack each other because even the victor would be greatly damaged by the economic repercussions. This was one of the driving forces behind the founding of the European Union and is cited as a major (if not predominant) reason why war between China and the United States is almost impossible in the current economic climate — which is one reason China is working hard to find other markets for its products so it has more options in its foreign policy, especially when it comes to such hot topics as Taiwan.
War between Canada, the United States, and Mexico was once a likely scenario and became reality in the War of 1812 and the Mexican-American War of 1848. Nowadays, war between the three countries is almost unthinkable, mainly because large percentages of their imports and exports circulate among each other-in Canada and Mexico's cases, the overwhelming majority of exports go to the US. Only 21% of the US's exports go to Canada and Mexico, but that's still 5 times more than goes to China.
Not just imports and exports of finished products, either: in some businesses the manufacture of products depends on parts coming from the other country. The automobile industry is the best example, with an automobile assembly line in Michigan installing engines made in Ontario made from parts from Ohio (or the reverse).
Not to be a downer, folks, but this same theory was applied to Europe between roughly 1870 and 1914. Didn't work out so well.
In the Florida Everglades, alligators have been the apex predator of the swamps. But now, Burmese pythons introduced by humans have invaded the swamps and have been found eating the alligators. Although the pythons are more of a threat to young, small alligators. The full-grown alligators are big enough that a Burmese python really couldn't swallow one; some have been found dead attempting to fight or eat alligators, but finding one alive after eating one is still unlikely. Really they're more an example of a Same-Size Fish; the problem is less that they eat alligators than that they compete with them.