When a small person is accosted by a larger opponent, most people expect the latter to win, but in fiction, the smaller a combatant, the more ass they can kick.
Like the Square-Cube Law going down, a combatant gets cooler and more badass the smaller they are. Short guys trounce giant bruisers, children routinely trounce goons, little people will be amazing wrestlers (if not literal ankle biters), and mice or smaller creatures (especially of the Talking Animal variety) will swarm and overwhelm, if not individually disable enemies with rapier precision.
There is some basis in science for larger proportional strength for smaller creatures: the Square-Cube Law works in the other direction. Although the volume, mass, and inertia of a half-sized humanoid such as a Hobbit is one-eighth a standard-sized human's, the strength of muscles is based on their cross sectional area, making Hobbits proportionally twice as strong as a human, and much more agile. This is also why ants are so strong compared to their mass. However, for this trope, Rule of Cool is in play whenever the Pint-Sized Powerhouse is as strong as, or stronger than, an average-sized human.
See also Apron Matron, for when small old ladies do this, and Mini Mook. Cute Bruiser, for when they're young, or at least very young-looking. Killer Rabbit covers "harmless" animals. See Weak, but Skilled for a common explanation behind this. Waif-Fu and Glacier Waif are subtropes. This Trope is often - but not always - associated with a David vs. Goliath fight.
- Anime and Manga
- Comic Books
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- Live-Action TV
- Video Games
- Web Comics
- Western Animation
- Real Life
- The Kithkin in Magic: The Gathering's "Lorwyn" and "Shadowmoor" blocks are a little under four feet tall, but are incredibly tenacious in a fight. In fact, the most common "classes" for them are Knight and Soldier.
- The Yu-Gi-Oh! card game has a few:
- Injection Fairy Lily is a cute and friendly-looking nurse (albeit one holding a huge syringe). If her Effect is used, her Attack Score rises to 3,400, stronger than Blue-Eyes White Dragon.
- Ultimate Baseball Kid. He looks like a ten-year-old little leaguer, but his effect grants him 1,000 extra Attack Points for every Fire-Attribute monster on the field (except himself) making him lethal in the right type of deck.
- Goblin King. Despite the regal name, he's a small guy who's a Level 1 monster with zero points, but he gains 1,000 points for every Fiend on the field other than himself. If used in combination with cards like DNA Surgery and Opti-Camouflage Armor, this can be very potent.
- Mokey Mokey. Being a Normal Monster, this guy at first seems even weaker than a Kuriboh. However, if the Spell Card Mokey Mokey Smackdown is used, these little guys become terrors, their Attack Scores becoming 3,000 apiece if a Fairy you control is destroyed.
- David 1, Goliath 0. David is a youngster at that point in The Bible, but depictions often make him even younger. David could even be the Trope Codifier, seeing as "David and Goliath" is a common term for a fight where a little guy is able to beat up a big guy.
- Thor's son Magni was the embodiment of strength. One myth states that Thor fought a giant named Hrungnir, but while Thor was victorious and killed Hrungnir, the giant's body fell on him, pinning him to the ground and leaving him helpless. After no-one else was able to so much as budge the giant's heavy corpse, Magni - who was only three days old at the time, was able to lift it off his father effortlessly.
- In Greek Mythology, Heracles is rarely depicted as "pint-sized". However, he certainly was on the day he was born, and on that day, Hera made her first strike against him, sending two venomous serpents to kill him while he slept in his cradle. He simply grabbed them both and crushed them, one in each hand.
- Thanks to the legacy of luchadors such as El Santo and Místico, the lightweight division title belts tend to be more prestigious in Mexico than the heavyweight division title belts.
- A "World Midgets Title" was established in 1949 by the National Wrestling Alliance. Though it did not have much longevity, the midgets proved strong enough to lift non midget wrestlers(There is one story of such a wrestler picking Gorilla Monsoon (who weighed 400 lbs) in a fireman's carry and carrying him around a ring). In 2009, Octagoncito won the newly established World Minis title, but it didn't get much use before becoming a strictly PWR title.
- The Mini Estrella Division, most commonly seen in Mexican promotions, was set up to give wrestlers who are simply too small to qualify even for the lowest weight classes(which were/are enforced by law) someone to compete against, although it sizes wrestlers based on height rather than weight, so size discrepancies are not entirely ruled out. While there are many mini estrellas who eventually outgrow the division, some have already hit their maximum height yet still find promoters finding ways to have them wrestle those far out of their weight/height class just because they are popular enough. AAA had the Mascot Division, made entirely of mini estrella and larger wrestler pairs, for example.
- Rey Mysterio Jr.: At 5'4" he is overshadowed by just about anyone he meets in the ring, but still often holds his own. Even more so when you consider that when he started as a teenager in Tijuana, he used to be smaller.
- Tazz, on a relative scale: at 5'9" and 240 lbs the average pro wrestler towered over him. Guess who was the toughest, hardest Badass in all of ECW?
- Bryan Danielson while larger than the average man, was only an inch taller and 50 lbs lighter than Tazz. Yet he used to use a butterfly suplex as his finishing move. An extremely delayed butterfly suplex.
- Thea Trinidad is barely five feet tall, but is a knockout tag team champion and has pin falls victories over noticeably larger wrestlers like Winter. Power really is not her stock and trade though.
- Nikki Bella is 5'4 but can lift every other Diva over her shoulders, and has a very power-based move set. She picked up a fucking man and held him for several seconds!
- Adrian Neville is a 5'10 high flier, but he can dead lift Kevin Steen into a German suplex.
- Paul Robinson of Progress Wrestling. There's no getting around the fact that the man is TINY. However, he's also a former kickboxing champion and not only defeated Jimmy Havoc in a BRUTAL hardcore match to become number one contender to the Progress Championship, he dominated champion Will Ospreay for a good portion of the subsequent title match and only lost due to a roll-up pin.
- The WWE Cruiserweight Classic had several of these. Contrary to popular belief, not all cruiserweights are high-flyers.
- Dragon Gate's roster skews shorter and leaner than most, even in Japan, and there are only one or two true heavyweights on the roster at any time; this means that while Don Fujii easily exemplifies the trope in a vacuum, he's not short by DG standards. Even so, El Lindaman is notable for being about 5'3" but powerful and well-built — he deals primarily in suplexes and judo throws. Peter Kaasa is around the same height, and while his style is high-flying, he has a massively muscled physique and great strength.
- John Silver of the American indies is as strong as he is short, and he is very short.
- Dungeons & Dragons:
- Any gnome or halfling who reaches high enough level. At 15th level, there's not much difference between human and halfling barbarians. While both races take a hit to physical strength, gnomes are extremely durable, being able to endure exertions like dwarves and orcs. Compared to elves, they are almost indestructible.
- Character generation can result in this too. Height and weight in D&D, Pathfinder, and many other games is not related to stats. So yes, that human girl who stands 4'11" and weighs all of 108 pounds? If you're lucky, she's a barbarian and is carrying the tools of her trade. If she prefers Good Old Fisticuffs though ...
- It's entirely possible in the 4th edition D&D to start as a Pixie Fighter with a 13 in Strength, meaning the creature that's no more than 4 pounds and a foot tall in, and is the only player race in the tiny size category, can carry 130 pounds without penalty, while making every fight a match against much larger sized foes.
- Blood Bowl has one of these in the form of the Goblin Fanatic. In a world that has trolls, ogres, daemonic beasts, treemen and dwarven warmachines — the unit with the highest physical strength is a tiny goblin who's 'roid raged on weird mushroom potions and rapidly swinging a solid steel ball and chain that's three times as big as he is.
- Pawns in chess can end up becoming this if they are in strategic enough positions. As a pawn is the least valuable piece, whenever one attacks any other piece, the other piece is usually forced to retreat. And if a pawn gets all the way to the other end of the board, it can decide the game by promoting to another piece (usually a queen).
- Mrs. Hawking of the Mrs Hawking play series fits this to a T. She is depicted as five-foot-two and a hundred and fifteen pounds of pure terrifying badass. She is an accomplished martial artist who regularly takes on opponents twice her size.
- Neopolitan is ostensibly the smallest human character in the series, standing around 4'11" including heels, but is capable of performing some seriously impressive acrobatic feats near the end of Volume 2 and outright overpowering Yang, who is a head taller than her.
- Nora Valkyrie is the smallest of the main eight protagonists at 5'1". That said, she is strong enough to wield a hammer bigger than her own body, and claims she can lift five times her own weight. When her Semblance is activated, her blows can render boulders into ash and break a stadium designed to take insane amounts of punishment.
- Whateley Universe: there are a number of students at the Superhero School Whateley Academy who would qualify, but the most notable is a petite middle-schooler named Desiderata Lopez. She can strike with a force of over eight tons with a fingertip. However, as is often the case in this series, that power comes at a terrible price: in her case, it is Power Incontinence, which means that she always applies 8 tons of force to anything she does, whether she wants to or not. her room looks like it was designed to hold the Incredible Hulk, Her computer is built so it takes 8 tons and 1 ounce of force to press the keys, otherwise she either couldn't press them at all or would demolish them. Her code name is Diz Aster. Poor kid.
- In The Cult of Scratchwood, Bren initially scoffs at the idea that the literally pint-sized Dalek Danny could harm him. Only, his laser gun isn't any less powerful than the other Daleks'…
- Reiko Ishida of Survival of the Fittest v4 is 4'9, which has been noted to technically make her a dwarf. However, she was a successful athlete before the island, having had a fair amount of recognition as a figure skater. On the island she manages to receive a fairly high body count; one death has her manage to beat a Huge Schoolgirl to death.
- In The Jenkinsverse, Humans are the strongest and toughest sapient race in the known universe. We are also one of the shortest.
- Bay 12 Sword Art Online RP: Shiina is the smallest player within the cast. She's also the party's tank and is capable of hitting as hard as The Big Guy, who's almost three feet taller than her.
- In a Captain Laserbeam episode of the Thrilling Adventure Hour, ex-Adventurekateer now-supervillain Tinker Taylor calls out Captain Laserbeam on always taking on every supervillain who came to Apex City. In particular he names the time that he abandoned chaperoning a field trip to the Pen and Paper Museum to fight Major Minor, the Minuscule Musician. What follows is a Long List of various miniature heroes:
Captain Laserbeam: Who else was going to stop his martial march of miniature musical mayhem?
Tinker Taylor: So many people could have done that: Mighty Mite, Guy Small the Small Guy, Little Hercules, Tiny Timothy, Short Attack, Willy Wee Warrior, the Homunculus, Space Midget, Scale Model, Robo-Small, the Itty-Bitty Hitting Committee, shall I go on?!