Similarly to ceratopsians, the thyreophoran dinosaurs (the stegosaurs and ankylosaurs) have a reputation of a tough prey for big theropods, often being referred to as the "tanks" of the dinosaur world.
Stegosaurs and ankylosaurs (especially the former) are also a frequent subject of Dumb Dinos, due to the fact that Stegosaurus is often stated to have one of the smallest brains among dinosaurs has contributed to this reputation.
Popular portrayals of armoured dinosaurs vary a lot in personality, but they tend to default towards being portrayed as tough, powerful, and none-too-bright, as well as having having large appetites. Occasionally, they will be portrayed as Boisterous Bruisers. In short, they have a reputation as Dumb Muscle.
Compared with ceratopsians, stegosaurs tend to appear more of a sort of Badass Gentle Giant dinosaurs — mostly placid and nonviolent, but still able to defend themselves if necessary. Ankylosaurs usually share the same treatment but tend to be more aggressive and temperamental than stegosaurs.
While stegosaurs can be either solitary or sociable among each other, ankylosaurs are usually depicted as aggressive, territorial loners.
Fictional stegosaurs are usually either Stegosaurus or its smaller, spikier relative Kentrosaurus, whilst fictional ankylosaurs will usually be Ankylosaurus itself, or occasionally Euoplocephalus and Polacanthus.
Like ceratopsians, ankylosaurs and stegosaurs will often be depicted facing off against the resident big theropod of their time period — for example, Stegosaurus is often shown battling Allosaurus, while Ankylosaurus often does this with Tyrannosaurus rex (and so does Stegosaurus on occasion, for that matter).
See also Beware My Stinger Tail, often applied to both stegosaurs and ankylosaurs. Compare with Temper-Ceratops, Gentle Giant Sauropod, Social Ornithopod, and Headbutting Pachy, which are other plant-eaters of the dinosaur world. For more information about depictions of the Stegosaurus in popular culture, see this link.
- In an early 1970s commercial for Cocoa Pebbles cereal, a factory is depicted where Fred Flintstone sends the cereal down to Barney Rubble via a Stegosaurus that acts as a conveyor of sorts. The spike motion is even reversible, as shown when Fred tries to get at Barney for eating the product rather than putting it into boxes.
- Jurassic Fight Club has one Stegosaurus stuck in a swamp that nonetheless manages to kill a predatory Allosaurus with its thagomizer, hitting it in the head to death when it seemed already hopeless and destined to die for starvation. The series also has a Gastonia fighting against a giant Utahraptor, winning the battle by using its stingy tail as a weapon.
- Planet of Dinosaurs shows a sleeping Stegosaurus in an arid hilly landscape, and another specimen walking lonely in the background of the scene. The sleeping stego is accidentally awakened by the human time traveller and reacts instinctively by hitting some scrubs with its tail, but then walks away peacefully. It's described by the host as a smart animal despite its "apricot"-sized brain.
- Walking with Dinosaurs: Stegosaurus and Ankylosaurus appear in the second and sixth episodes. Both are portrayed as large, dim-witted, aggressive herbivores that will attack anything that they see as a threat, and are depicted as facing off against the setting's large theropod.
- Fantasia: A Stegosaurus fights and loses a battle against a Tyrannosaurus rex because it's too slow-running, while ceratopsians and hadrosaurs, both faster, flee the predator. The stego, however, before losing and dying, hits and wounds the rex with its tail. It's shown as a sluggish creature unable to run because of its stubby legs, but this is due to the film being made in 1940.
- Ice Age 3: Dawn of the Dinosaurs:
- An Ankylosaurus is amongst the dinosaurs inhabiting the hidden subterranean world full of dinosaurs. It's incredibly aggressive and ill-tempered and tries to attack the gang, which only loses it thanks to Ellie managing to trick a nearby Brachiosaurus into providing them a means to escape. Despite its aggression, it's still seen cowering in fear of Rudy the Baryonyx.
- The other armored dinosaur seen inhabiting the hidden world is Kentrosaurus, which are among the dinosaurs menacing the herd after they escape from the above-mentioned Ankylosaurus.
- The Land Before Time:
- Spike, one of the five main dinosaurs, who serves The Big Guy of the group: mute and lazy, but still strong and altruistic. He's a Stegosaurus with big head and small undersized plates and spikes like real-life baby stegosaurs. He's also a Big Eater, and a Kind Hearted Simpleton. But in the trip toward the Great Valley he reveals himself to be courageous and tough, especially in the scene of the first film in which he pulls tenaciously a big rock with his head together with Littlefoot, to make the rock falling down and hopefully hitting the head of "Sharptooth" below (the villainous T. rex who has pursued them throughout the journey).
- The original movie also contains an aversion of this trope in the form of Rooter, an elderly Scolosaurus; at first glance, he appears menacing, but immediately reveals himself to be wise, gentle, and kind-hearted toward poor Littlefoot (who had lost his mother in the previous scene). Rooter is very slow-moving, walking like a giant tortoise, and has wrinkled lips and neck, thick eyebrows, and only one tooth left, revealing he's very old.
- Url from ''Dinosaur is an aversion. He acts more like a playful puppy than an armored juggernaut, and when danger threatens he's much more likely to cower and hide than fight.
- Jurassic Park:
- The Lost World: Jurassic Park has Stegosaurus. They appear rather aggressive toward the humans to protect their young at a first glance, but this is only because they wrongly believe to be menaced by them, or because they feel themselves disturbed by the humans, while the latter are actually friendly toward the animals, though wary because of their size and number (stegos here are herd animals).
- Jurassic World: The Ankylosaurus is notoriously one of the few herbivores that visitors cannot interact with at the petting zoo since it is moderately aggressive. One of them later fights the Indominus rex and manages to bash her face with its tail, before the predator gets the upper hand by flipping it on its back. A big carnivorous dinosaur overturning an ankylosaur to bite its soft underbelly is a common sight in paleo-art.
- King Kong (1933): A Stegosaurus is amongst the prehistoric animals encountered. Acting similarly to a rhino, it charges angrily towards Carl, Jack, and the Venture crewmen with them on sight without provocation (outside possible territoriality matters) and takes at least two gas bombs and multiple gunshots to go down. It also noticeably has a tail long enough to have eight spikes on it instead of the usual four.
- Raptor Red features Gastonia, though in the book it's erroneously described as having a club tail. Gastonias are generally left alone by Red and other Utahraptors, though her mate is from a family that figured out a way to successfully hunt them and he teaches her. Another scene sees a young Acrocanthrosaurus try to take a bite and lose a tooth to its tail club, convincing it to go hunting for less tenacious prey.
- The original novel Carnosaur by John Brosnan featured Scolosaurus among the featured dinosaurs. Like practically every dinosaur in the book (except, needless to say, the Brachiosaurus) it's aggressive to an absurd degree, going so far as to destroy a tank with its tail club!
- Banjo-Tooie: The common baddy of Terrydactyland are small stegosaurs called the Bargasaurus, which attack Banjo on sight by barging into him. When Banjo turns into a Baby T. rex the Bargasaurus do not attack (although they can still damage him) and will even teach him how to roar.
- Jurassic Park
- Jurassic Park: Dinosaur Battles: The Stegosaurus that serves as the end boss of the first map guards the bridge to the second map and doesn't allow anyone to bypass it. An Ankylosaurus in the third map subverts this as, in addition to being territorial, it's smart enough to set up traps that would take away some of your dinosaur's health before battle.
- Jurassic World: Evolution: Stegosaurids and Ankylosaurids, like any other dinosaur have specific needs and can get very fussy if they aren't met, usually being prompted into breaking out of their enclosures. Some, like the Ankylosaurus are rather notorious in that regard as they would rather be in more spacious enclosures with lesser dinosaurs compared to most herbivores.
- Plants vs. Zombies 2: It's About Time: Stegosaurus and Ankylosaurus appear as stage hazards in the Jurassic Marsh. The former is depicted with a goofy smile, though it will stare at the screen with a bored expression if it's unable to hit the zombies with its tail. The latter also has a dopey design, but holds its spiked tail above its head like a scorpion, denoting that it's more disruptive and harder to deal with than the other dinosaurs.
- Pokémon Sword and Shield: The eighth generation games feature the ability to revive fossils as is usual in the series, and one of them is some sort of Dragon-type stegosaurid... the back half of one, anyway. By carelessly combining it with the front half of a velociraptor or dunkleosteus, the player winds up with the rather goofy-looking Dracozolt or Dracovish, both of whom are described as having difficulty existing in general — despite the resident paleontologist Cara Liss's claims otherwise.
- Saurian: Ankylosaurus is one of the six confirmed playable dinosaurs in the game. It is the most territorial herbivore in the game, only tolerating members of its own kind during mating seasons and competing against even other herbivores regarding its diet. As a realistic simulation of the Hell Creek Formation, players are forced to play Ankylosaurus as a territorial animal.
- Star Fox Adventures averts this with the Thorntails, a tribe of peaceful and harmless nodosaurs.
- Darkwing Duck: Stegmutt is an anthropomorphic duck turned into an equally anthropomorphic Stegosaurus by a Devolution Device. He's a Gentle Giant Dumb Muscle who is initially the incompetent and not very malevolent henchman of the villainous Dr. Fossil, but he joins the Justice Ducks after his HeelFace Turn.
- Extreme Dinosaurs: Stegz (a Stegosaurus, naturally) and later Hardrock (an Ankylosaurus). Both are shown as musclebound, barechested anthropomorphic dinosaurs. In an inversion of the stereotypes of stegosaurs as Jurassic dimwits, Stegz is the team's thoughtful Gadgeteer Genius. Meanwhile, Hardrock is more of a Martial Pacifist despite his fearsome appearance.
- The Transformers:
- Snarl the Dinobot transforms into a Stegosaurus. Like all the Dinobots, his intelligence varies considerably depending on the continuity, but even in the cartoon, where the Dionobots genuinely are idiots he's not the dumb one of the team (that honor goes to Sludge the Brontosaurus). He is, however, exceedingly tough and very mean and aggressive regardless of the continuity.
- Soundwave's cassette, Slugfest, is also a Stegosaurus. He's always stupid regardless of the continuity. He's also The Berserker, flying into a rage at anything he doesn't understand (and since he's an idiot, that's just about everything).
- Like Url from the Animated Film folder, Bumpy from Jurassic World: Camp Cretaceous averts this trope by virtue of being an atypically cute and shy Ankylosaurus who doesn't do much in the way of fighting.