* [[http://imgur.com/gallery/lIJE1 THIS rabbit.]]
** Indeed, rabbits are an actual example. With those teeth, they can inflict quite a bit of damage, and rabbits are hardly docile creatures. Male rabbits will rape so that they can breed like rabbits, and ''[[GroinAttack castrate]]'' rival males to ensure their own breeding rights. Yeah. [[NightmareFuel Rabbits castrate each other with no anaesthesia]]. They also headbutt, and their kicks pack quite a bit of power for their size, to the point that they can break their own spine if they kick hard enough. Some rabbits are known to [[http://www.cairns.com.au/article/2009/09/15/63975_local-news.html attack snakes]]. One gained fame for trying to [[http://en.wikipedia.org/wiki/Jimmy_Carter_rabbit_incident board Jimmy Carter's fishing boat]] in 1979. It even was nicknamed "Killer Rabbit" by the media.
*** There was also a story circulating in Russia about a naturalist who observed a rabbit attacked by an eagle turn on his back and eviscerate the eagle with the claws on it's hind legs. The eagle apparently died a horrible death.
* The Secretary Bird of Africa is another example. They look very cute and seem relatively harmless at first, but they are actually ferocious predators. They very closely resemble [[RaptorAttack the small predatory dinosaurs known as raptors]] that lived millions of years ago, such as Velociraptor and Troodon. They are endowed with a sharp, curved beak and razor-sharp claws on their feet. Their kicks are very powerful, and they regularly prey on snakes. They snap the snake's spinal cord with their kicks, and then proceed to tear up its body with their claws and beak and eat it. They can be very aggressive towards humans sometimes, and they can allegedly shatter a human hand with a kick. In other words, if you're looking for a living, real-life [[JurassicPark Jurassic Park]], look no further than this.
* The prehistoric ''Bullockornis'' resembles a human-sized duck. With a viciously sharp beak and a carnivorous appetite, the ''[[FanNickname demon duck of doom]]'' makes Velociraptor look like an adorable bunny in comparison.
** Actually, ''Bullockornis'' and other dromornithids are now considered to be herbivores. Though, given what modern herbivores like the other infamous aussie bird, the cassowary, can and will do, this isn't much reassurance.
** Speaking of which, Velociraptor ''itself'' is an example of this trope. Even when it doesn't look like the one in JurassicPark, a coyote-sized, feathery chicken-like dinosaur is perfectly capable of taking on a full-grown Protoceratops.
* Domesticated dogs and cats still have hunter's instincts, and will often attack small animals they come across even if they're not hungry. Cats in particular, due to their mobility and stealthiness, are well equipped to hunt down various small animals such as birds and rodents that might be lurking in your back yard. Because they don't need the food, cats will often just play with their catches rather than eat them. For an added bonus, cats have a lot of bacteria in their mouths, which can make their bites surprisingly nasty - second only to that of a human being, in terms of infectiousness. (If you are bit by a cat, ''go get medical treatment!!'') Cats were largely domesticated because their ancestors' presence was tolerated due to them being very good at pest control, which became extremely important around 10,000 years ago when humans decided to settle down and take up agriculture.
** Dogs are also famous for attacking other people and even large predators that decide to [[BerserkButton threaten their owner]]. This is expected from large breeds like rottweilers, but even the smallest of dogs are known to turn absolutely fierce when their master is in danger. Cats have also been known to do this, but much less often.
* [[http://en.wikipedia.org/wiki/Koala#Ecology_and_behaviour Koalas]]. It's not hard to piss them off, especially if you interrupt one of their 19 hours of sleep, and they have huge teeth and claws that can do some real damage when you rile them up. [[LandDownUnder Please stay away from them.]] Fun fact: they are always [=POed=] at you because they're coming down from a high. Eucalyptus leaves actually contain a mild toxin, to which they have built up a resistance that instead makes them stoned. Hence the sleeping 19 hours a day.
* [[http://en.wikipedia.org/wiki/Wombat#Wombats_and_humans Wombats]] can do a fair amount of damage too - one naturalist ended up with a 2cm deep bite in his leg. Through a gumboot, trousers, and thick socks. And if they get some speed up (40km/hr at maximum, despite being generally slow) they can knock grown men over. This being [[DeathWorld Australia]], their main defence against predators is to hide in a hole and use their cartilage-heavy, armour-plated arse to keep themselves from serious harm -- and their modified pelvic bone that forms the aforementioned armor-plating is sturdy enough to crush a dingo's skull, if one manages to get its head into the hole before it's completely blocked off. Australia is potholed to DeathWorld for a reason.
** There's been instances of cars hitting wombats and flipping over. The wombat was fine. The car? Not so much.
* The platypus looks like an adorable beaver-duck, but the poisonous stinger of the males contains one of the nastier venoms known to man. It causes immediate hyperalgesia in humans, which is acute hypersensitivity to ''pain'' that can't even be dulled by painkillers without resorting possibly lethal dosages and can last weeks to months. Yikes! In other words: it won't kill you, but it will ''make you wish that it did.''
* The kangaroo. Awww, itsh godda baby in itsh pou[[OhGodWithTheVerbing OH GOD, THE PAIN, WHAT WITH THE KICKING AND THE RUPTURING OF THE ORGANS AND THE CRUSHING OF THE BONES!]]
** You know how a kangaroo likes to deal with dingo predators? [[DeathTrap By luring them to a lake, pulling them in one by one, and]] ''[[DeathTrap drowning them]]''. Kangas are not afraid to kill.
** Big truck crashes into kangaroo. Kangaroo wins.
* Due to causing vehicular accidents, the deadliest animal in the USA is the deer. Moose are even worse. Think you're safe in your two-ton cage of speeding metal? Think again! Hitting a deer or moose can easily cause a fatal accident. Moose legs are also uniquely suited to slide up a car hood and through the windshield in a collision.
** Not to mention their antlers, sharp hooves, and teeth. An annoyed horse will just bite your hand really hard then let go, to tell you stay away. A deer that thinks you're trying to kill it, however, bites your hand ''then tries to rip your hand off''.
** Red deer regularly devour birds, rodents and even smaller deer.
* While emus don't fall under the generally accepted category of "cute", they are essentially human sized birds with fluffy feathers and big, expressive eyes. They can also kick you to death in a matter of seconds. Most of those tall, long-legged, flightless birds aren't that harmless. Ostriches are reputed to be able to disembowel a lion.
** The emu's relative the Cassowary is essentially a Velociraptor with a beak. Also, EyeScream, they are attracted to shiny objects, like human eyes. Which are at beak level. The cassowary, a [[http://www.thewonderofbirds.com/cassowary/cassowary.gif rather silly-looking]] flightless bird best known for having an oddly-shaped head, also sports a set of claws that make it pretty much [[http://i65.photobucket.com/albums/h225/centrarchid/6a00e398be6a750005011016c13c18860d-500pi.jpg the closest modern-day equivalent of a velociraptor]]. If you manage to piss one off, it can and will eviscerate you, and there are numerous cases of death-by-cassowary on record. They have been known to [[ExtremeOmnivore eat metal]].
*** In other words, these guys are the last of the Old-School Dinosaurs.
* The blue-ringed octopus. Not exactly cute, but it definitely wouldn't look very threatening, despite being one of the most poisonous sea creatures known to man. As comedian Billy Connolly says "It wouldn't fit in the palm of your hand, but if this thing's in a bad mood ''you don't make it to the ****** phone!''"
* Octopi are mostly known as tiny and occasionally even cute little animals that have amazing abilities of fitting into the smallest cracks and change their skin to match any surface. So when the staff of a marine aquarium decided to move their North Pacific Giant Octopus into a tank with their sharks, they didn't expect it to have any trouble staying safe. [[http://www.youtube.com/watch?v=cA8zQw6gDNI And then each night more and more of the sharks were disappearing or found dead]].
* Mustelids (ferrets, minks, weasels, martens, sables, polecats, badgers and wolverines) are unbelievably strong for their size. They are not afraid to fight back fiercely when [[http://www.youtube.com/watch?v=WGF-pofc-lQ threatened by greater predators]], despite their cute, fluffy appearance. There's a reason why [[PersonAsVerb badger is a verb]] and {{Wolverine}} is a superhero.
** It should be noted, though, that the European Badger is a shy social animal (they live in small family groups) that prefers to avoid confrontation and will only fight back when it is unable to escape. The badger's dubious reputation as a feriocious animal actually comes from the old "sport" of "Badger Baiting". Which, sadly, pretty much consisted of trapping a badger and forcing it to fight to the death against hunting dogs.
** The badger's reputation of reluctant ferocity and toughness is well deserved. Their skulls and hides are incredibly thick, and layered with tough muscle that makes them highly resistant to 'cudgels, blades, and shot' according to monographs from periods when they were hunted. In addition, their burrowing claws are capable of doing massive damage. Oh, and that thick skull? Its built in such a way that once a badger locks into a bite it must be dislodged with crowbars. Post-mortem. BewareTheNiceOnes indeed.
** Wolverines, in particular, are ''dangerous'' little bastards. In the regions where they still thrive as a species, they've killed the most people. This is because they are very territorial and easily irritated - bears will usually leave you alone if you're not in the immediate vicinity of their young, but wolverines consider you a threat simply for being on their territory. Once they get your scent, they chase you, and they don't stop until you're dead or well out of their territory, preferably dead. Grizzly bears are known to give these things a wide berth. ''Grizzly bears.''
** Even the weaker ones, such as the Least Weasel and the Stoat, despite looking shy and fragile, are actually capable of killing prey twice their size. Even the much stronger Wildcat and the aggressive sewer rat will usually avoid confronting them. Indeed, Least Weasels are known to go down into rat nests and kill everything there.
* And then there's the Honey Badger, their more irritable African cousin. The [[http://en.wikipedia.org/wiki/Honey_Badger honey badger]] is kinda cute, but it has thick, tough skin that acts as some sort of body armor, giving it some protection against the claws of large animals such as lions. Its skin is too thick for the fangs of venomous snakes to penetrate, so it can eat those. It sometimes attacks (small) crocodiles. There's a ''reason'' "Honey badger don't care" became a meme.
** These things have been know to chase off, if not kill full grown ''lions''. How? it uses its small size and speed to run right under the lion, [[GroinAttack and try to rip its balls off]]. Also, these little guys will growl, hiss and charge at their attackers to frighten them away. And, if that doesn't work? They produce a rather foul smell from their behinds, much like skunks. And, yes, it's quite effective in driving predators away. Oh, and the name? Comes from the fact that they really like honey, how does it get said honey? By shoving its face into an occupied bee hive and chowing down while ignoring the bees protests, and keep in mind, these are African honey bees, aka the granddaddies of ''Killer Bees''.
** They're also very smart, being one of the few animals that have been documented using tools; a Honey Badger was filmed using a log to help it reach a small bird that was tangled in some vines.
* The Giant Panda. Another contender for "cutest bear" (it ''is'' a card-carrying member of the bear family, as shown by molecular genetics), a truly ridiculous amount of time, effort, and money has gone into saving these fat and lazy animals. Some people might think pandas are vegetarians because they only eat bamboo. They only eat bamboo because it's one of the only things that can't outrun them, being plants. Give an adult 200 pound panda a chance, and it will kill and eat small animals, possibly including children. Fun fact: Pandas actually have a carnivore digestive system. Its round face is the result of powerful jaw muscles, which attach from the top of the head to the jaw.
** A ''National Geographic'' article once told about a panda named Zhen Zhen who terrorized a camp, demolishing tents and attacking people.
* A article in the London newspaper ''Metro'' involved a viper that was rescued from a house in China. The rescuers tried to feed it a live mouse and the mouse ''killed it'' after a half-hour struggle. They could only theorise it had run out of venom during the capture.
* [[RidiculouslyCuteCritter Raccoons]], anyone? They look like fuzzy little puppy-cat things with domino masks, but their teeth and claws can kill pets and send people to the emergency room. To top it off, they're the biggest carrier of rabies in North America (though domestic dogs are the biggest rabies vector in general). That's not mentioning the fact that they also tend to have really, really nasty tempers and utterly zero fear of humans.
* Dachshunds, a.k.a. wiener dogs. They look ''adorable''. They're also bred to go into badger holes and ''lure the badger out'', making them cute Killer-Rabbit Killers, or at least the [[HyperCompetentSidekick Hyper Competent Sidekicks]] thereof. [[http://www.cracked.com/article_16471_wolves-in-sheeps-clothing-badass-roots-5-sissy-dogs.html It should be no surprise the dachshund was also used to hunt wild boar in some instances. Hell, drag them to Africa and take them on a big cat safari. They just don't give a fuck. It is a good day to die.]]
** There's at least one known instance of a Dachshund killing a [[AngryGuardDog very, very aggressive German Shepherd]] by luring it under a parked car and, using its smaller size to maneuver, tearing its throat out. Helps that their teeth are ''not'' a small dog's teeth.
* Popular perception of dolphins pictures them as happy and cheerful, but their bodies have more than enough strength to severely hurt and even kill sharks and humans, two species of badass apex predators. Dolphins also tend to torture their prey before killing them. And then there are the bottlenose dolphins, which could very well be described as Flipper's evil twin. Also, dolphins will try to fuck AnythingThatMoves, and will rape ''you'' if they get half a chance. [[SlasherSmile Think twice about their smile]].
** [[RuleThirtyFour Turnabout is fair play!]]
* There are some tree frogs, small and rather beautiful. And whether they are alive or dead, merely ''touching'' them with one's bare skin is a bad idea. With [[PoisonedWeapons a tip of blowgun dart]], on the other hand.... Fortunately, the ones in captivity are not fed the ants that cause them to produce said toxins.
* Shrews are fuzzy and tiny, which is a recipe for textbook cuteness. Gram for gram, they're also the most voraciously-bloodthirsty predators on the planet, killing prey many times their own size and eating anything that moves, and consuming triple their body weight ''daily.'' Some of them have venomous saliva as well, so be ''glad'' these things are so little.
* Chimpanzees. Most funny and human among the whole lot of [[EverythingsBetterWithMonkeys funny monkeys]], right? In reality they are insanely strong (a 70 kg male can lift up to 300 kg; less surprising when you take a look at [[http://farm4.static.flickr.com/3202/3024567966_4ffe563ebd.jpg those muscles]]) and ''very'' dangerous when pissed off. Some have killed adult people and even kidnapped and eaten human babies. Intra-species murder, wars between bands, and even cannibalism aren't unknown in them either. And yet people still think worse of the comparatively [[GentleGiant harmless gorilla]]...
* Pigs are generally thought of as ugly, fat, listless, and generally harmless creatures... unless you are a pig farmer. Editor has been told that a farmer being trampled (and subsequently ''eaten'') is not unheard-of.
** Modern swine are ''much'' more docile than their Iron Age ancestors, which were more like barely tamed boar. In AncientRome, pig farming was infamous for the extreme danger involved.
** Perhaps best illustrated by the attitude of the veterinary profession. Cows that can kick and gore and break bones? Stocks, tranquilizer, good to go. Horses that can do the same? Experienced equestrian, tranquilizer, no problem. Sheep? Pshh, sit 'em on their rumps, end of problem. Pigs? WE NEED LOTS OF DRUGS AND HALF A DOZEN NURSES AND A FARMER WITH A METAL CATCHPOLE AND A REALLY STURDY METAL PEN AND EXCELLENT EARPLUGS AND IF I DON'T MAKE IT OUT HERE'S MY WILL.
* While [[ALoadOfBull Bulls]] are already perceived for being badasses, ''[[http://www.themorningstarr.co.uk/2009/08/18/farmer-killed-by-his-cows/ Cows]]'' aren't that much far behind in that regard.
* Squirrels are cute, nervous, and fuzzy. Harmless, right? Or are they [[http://news.bbc.co.uk/2/hi/4489792.stm arboreal piranhas]]?
* The [[http://en.wikipedia.org/wiki/Conus Cone Snail]]. Many people pick them up because they're pretty... and get a deadly neurotoxic harpoon stuck right into them! Due to the speed at which the snail fires the harpoon, they are actually the ''fastest snails on earth''.
* From the right perspective, jellyfish can look like gracefully-flowing gossamer, living chandeliers. But one touch and you'll know what days of agony is like ''if you're lucky''; if not, and it's one of the nastier species, you'll learn what a few minutes of agony ''and'' the afterlife are like.
* Man-o-wars. Look like jellyfish but are really a colony of different organisms where one is a purple floating sac and the rest are tentacles that make digestion and attack. From outside the water, [[http://upload.wikimedia.org/wikipedia/commons/thumb/c/c3/Portuguese_Man-O-War_(Physalia_physalis).jpg/437px-Portuguese_Man-O-War_(Physalia_physalis).jpg it looks beautiful]]. Under the water, they are goddamn painful and, in some cases, can kill a person.
* [[http://scienceblogs.com/tetrapodzoology/2009/09/great_tits_murderous_rapacious.php Great tits]]. They're relatives of the chickadees, have a [[HaveAGayOldTime name that induces giggles]], and in winter they prey on hibernating bats by ''ripping their heads off''.
* Chow Chows basically just look like big balls of fluff, but they have a reputation for being aggressive - to the point that the words "chow" or "chow mix" are basically code for "''be on your guard''" in your average veterinary clinic.
** Pit Bulls and Rottweilers go for your limbs, to hurt you. Chows go ''for your throat'' to '''go for the kill'''.
* Sloths. They're big, sleepy, slow-moving critters... living in jungles. Y'know, where EVERYTHING tries to eat you. Think about that for a second.
* The sloth's ancestors were roughly the size of elephants and could basically do whatever the fuck they wanted without having to fear predators.
* Anteaters don't even have teeth, but they've got claws to compensate. And if you ever see one of these walking on their hind legs, run. It wants to hug you, and if you put two and two together, you'll realize it isn't a friendly hug (the biggest anteaters kill predators that way).
* The [[http://www.youtube.com/watch?v=vB5recdpPaI clione,]] nicknamed the "sea angel," sure looks pretty as it peacefully swims through the water...until it [[http://www.youtube.com/watch?v=xlc7r34Sh-c opens its many-tendriled mouth to catch its prey.]]
* Poison ivy is gorgeous. It has glossy green leaves which are red when new, and a stunning purple fall color. It also has attractive white berries that birds love. It causes ferocious allergic reactions. Once it's on the skin, most efforts to alleviate the pain will only serve to spread the irritant oils. It grows quickly, and with its berries so appealing to birds, spreads rapidly. If burned, its irritants will be carried in the smoke, and will tear up the lungs of anyone who inhales that smoke. It also seems to be responding to elevating atmospheric carbon dioxide levels by increasing the potency of its irritants.
** On the other hand, half of the population likely to be exposed to it is just flat out immune. Amusingly, when the ''Series/MythBusters'' attempted to test poison ivy home remedies, none of them proved to be susceptible, though admittedly it could conceivably have been a false negative, as it's possible they had never been exposed to it before[[note]]Kari was banned from the test due to prior severe reaction, and Grant said on-air that he'd had reactions before[[/note]]; like all allergic responses, the initial exposure does not produce an effect but every exposure thereafter does.
* Skunks. They're cute, gentle, and will totally ruin your day if you even make a wrong move around them.
* A ''lot'' of plants look totally harmless but are actually quite dangerous. For instance, [[http://en.wikipedia.org/wiki/Nerium_oleander Oleander]] has beautiful flowers but it is ''very'' toxic.
** Special mention should go to teddy bear cholla, a cactus which, despite the name, is phenomenally un-cuddly. The name comes from the fact that it looks almost fuzzy, which, combined with the strange shapes it tends to grow in, makes it look kind of comical. The "fuzz," however, is actually thousands upon thousands of hair-thin, transparent, barbed thorns that come out at the slightest touch and lodge in your skin. Guess [[BearsAreBadNews bears are REALLY bad news]].
*** Honourable mention must go to the giant stinging tree. It does the same while looking EVEN more unassuming. One slight breeze and everything in a 3 block radius suddenly feels like it's ON FIRE!
* [[http://en.wikipedia.org/wiki/Grasshopper_mouse Grasshopper mice]] are tiny, fuzzy, and cute. They also howl like wolves and supplement their usual diet of insects with the occasional snake.
* Inverted with the Hickory Horned Devil caterpillar, the largest caterpillar in North America and larval form of the [[http://en.wikipedia.org/wiki/Citheronia_regalis regal or royal walnut moth]]. It's five inches long, covered in menacing-looking spines from head to end, and yet it's completely and totally harmless.
* But played straight with the [[http://en.wikipedia.org/wiki/Megalopyge_opercularis puss caterpillar]]. Awww, isn't it cute and furry, like a little [[Series/StarTrekTheOriginalSeries tribble]]? Until you touch it, that is, at which point you're in for a world of pain.
* Show breeds of Cocker Spaniel are subject to a phenomenon known as "Cocker Spaniel Rage," in which they flip out and attack for no apparent reason. That's right, ''[[Disney/LadyAndTheTramp Lady]]'' may one day try to kill you out of the blue.
* [[PintsizedPowerhouse Chihuahuas]] have a lot of bad temper and use to attack in packs, like a horde of angry rats. Some people have been savagely mauled by packs of the tiny bastards, including a police officer in a 2005 incident. Makes one wonder why ParisHilton is fond of them...
* Leopard Geckos are adorable, harmless-looking desert lizards, more well-known for their easygoing nature as a pet than for their '''[[BadassAdorable ability to kill venomous scorpions twice their size]]'''.
* [[SwansASwimming Swans]]: graceful, regal, a symbol of love ... and equipped with wings strong enough to break your arm at a blow if you come near their eggs.
* [[http://www.wired.com/wiredscience/2011/02/in-the-web-of-the-velvet-worm/ Velvet worms.]] Probably another UglyCute example, but they're soft and squishy things that crawl slowly over the forest floor on stubby legs. And are predators. That can kill prey the size of tarantulas. (They do it by spraying a [[CrazyAwesome sticky slime that quickly hardens into a net]] to trap their prey. And then they close in and eat the helpless prey alive.)
* [[http://icanhascheezburger.com/2011/10/08/funny-pictures-videos-lemming-fury/ Norway lemmings.]] Some local names for them reportedly translate to killer mice!
* Moles. That's right, the blinky/blind, fuzzy, [[TheWindInTheWillows shy-but-friendly]] little guys. These guys may be cute, but they are vicious little blighters: they are predators capable of hunting underground, and burrowing their own tunnels to do so, and are incredibly territorial. Oh, and cannibalistic- put two moles together for any length of time and you end up with one fat mole.
* Do not go to pet a dingo. They might look like Labrador Retrievers, but they're very much not domesticated, so for the love of god and for the love of your future children, do NOT pet it!
* Tasmanian devils. They're actually much cuter [[http://upload.wikimedia.org/wikipedia/commons/f/f0/Young_tasmanian_devil.jpg in real life]] than the cartoon character, but they are obligate carnivores with the strongest bite of any mammal, able to take down prey as large as a kangaroo. Not to mention they're ''extremely'' tempermental and loud.
* Inverted with the Horseshoe Crab. They have dangerous-looking spikes on their tails and bodies and tails that look like stingray tails, but they're harmless and can't really hurt you.
* The mantis shrimp is a small, often colorful little critter that lives in coral dens and mostly keeps to itself. To eat its dinner of molluscs and crustaceans though, the mantis shrimp doesn't bother with prying them open: it [[http://www.youtube.com/watch?v=i-ahuZEvWH8 BLASTS]] them open with its clublike arms, which strike with the acceleration of a .22 BULLET. The force generated per area is so powerful that the mantis shrimp can [[http://en.wikipedia.org/wiki/Mantis_shrimp COMPLETELY MISS its target and STILL do damage]] by force alone. Captive mantis shrimp have been known to crack or shatter aquarium glass with a single blow. They have another name: [[NamesToRunAwayFromReallyFast thumbsplitters]].
** See also The Oatmeal's comic about mantis shrimp as "[[http://theoatmeal.com/comics/mantis_shrimp the harbinger of blood-soaked rainbows]]."
* An awful lot of tropical reef fishes and invertebrates, including the drop-dead gorgeous ones popular for saltwater aquaria, are deadly poisonous, and even the nonvenomous species may sport razor-sharp spines for protection. Heck, even the ''coral'' can cut you to ribbons if the current makes you bump into it.
* Shrikes are small, cute songbirds that kill mice and lizards by [[ImpaledWithExtremePrejudice impaling them on thorns]], then use the neatly strung-up corpses as a larder.
* Most large frogs, but special mention goes to the American Bullfrog. Funny-looking, not particularly fast, no obviously deadly attributes. But it will eat anything. ANYTHING. In Southwestern areas, it will jump out of the water at night to hunt lizards, rodents, ''scorpions and tarantulas.'' If a scorpion is too big to swallow, it will chomp down on it, then fold it in half with its forelegs and shove it down its gullet.
* Pretty much anything that isn't newborn and isn't obviously dangerous has potential to be this. Natural Selection is the biological equivalent of TrainingFromHell on this planet. Even the vegetarians can rip the unwary a new one. Hell, even the ''vegetables'' can!
* Inverted with Crane flies. They may look like gigantic mosquitoes, but the worst a crane fly can do to someone is when they're larvae. Then they can do some damage to your lawn.
* Often rats in many cases. Not only do rats tend to look a lot more aggressive and disease-ridden than their other rodent cousins such as the mouse, they can ''be'' more aggressive, and are just as susceptible to carrying and spreading contagious diseases. And can be even worse pests than mice in many cases. Inverted with domesticated rats, which are sweet-tempered and friendly despite their species' bad reputation.
* Patterdale terriers and Jagd terriers (German hunting terrier) are still used for boar hunting and vermin hunting. Unlike many dogs, they still have the original strength and ferocity since they did not become just show dogs like dachshunds.
* The more brightly-colored and striking an amphibian is, the more poisonous its skin is likely to be. This also applies to insects, fish and reptiles. Its theorized that these bright, striking colors act as a warning for predators that says "do not eat me, I'm poisonous". Some species, such as the king snake, go so far as to imitate this look despite not being poisonous themselves.
* The Hippopotamus species have a popular reputation of being fat and contented creatures. However, they are highly territorial and kill more people in Africa than lions. ''Including killing lions''. And despite their huge size they can outrun humans. To put this in perspective, Steve Irwin, the CrocodileHunter, described a short boat-ride over hippo-occupied water as the ''scariest'' moment of his life. ''[[CrazyAwesome Steve Irwin]]''.
* When people think of seals and other pinipeds, they tend to visualize the cute, adorable circus or aquarium animals that have been trained to honk horns or bounding happily on the beach. People even consider them to be the sea's equivilant of a dog. However, sea lions are immensely aggressive and have been known to seriously maul humans, in addition to routinely killing each other. Antarctic expeditions have been attacked and at least three people have been killed by [[http://en.wikipedia.org/wiki/Leopard_seal leopard seals]] in the past. And if they climb up onto docks, or even into cities? Don't try to approach them. It ''will'' end in a visit to the hospital, possibly without one hand. Oh, and those goofy-looking elephant seals? You know, the big ones with the silly, drooping noses? [[http://www.youtube.com/watch?v=z7KsXwO6Ymw Here's a video of one having a disagreement with a parking lot]]...looking strangely adorable while doing so.
* The pelican, a waddly goofy looking bird with a weird neck and beak pouch, the larger ones can eat a pigeon in one swallow.
* A Belorussian man was attacked and killed by a '''Beaver''', similar, non fatal attacks have occured in other places.
* If you think snakes are cute at all, baby venomous snakes fall under this, especially baby cobras. They have huge eyes and a cute stripey pattern. They're no less venomous than adult snakes, and sometimes even inject ''more'' venom than an adult snake would, [[PowerIncontinence because they haven't learned how to use it yet.]]
* One of the biggest warnings that anyone will receive when doing amateur diving on or near tropical coral reefs is "don't touch the fire coral". Fire coral isn't a true species of coral, its actually more closely related to jellyfish and anemones. [[http://upload.wikimedia.org/wikipedia/commons/9/9c/Millepora_alcicornis_%28Branching_Fire_Coral%29.jpg This is what one variety looks like]]. Like jellyfish, they have nematocysts, which shoot out and deliver venom into anything that touches the fire coral. If you so much as brush one with your bare skin, you will be in some of the worst pain of your life.
* [[SubvertedTrope Subversion]]: Siberian musk deer. Seen from afar, it's an adorable bambi. Seen from up close, it's an adorable bambi with creepy vampire fangs. Despite the look, it's not a particularly dangerous animal.
* [[HumansAreWarriors Humans]]. We are much cuter ([[MostWritersAreHuman from a human point of view, at least]]) and weaker than many animals, and yet we can eat things that are not supposed to be eaten by anything (spicy foods are supposed to be repulsive to mammals, potatoes, almonds and many other foods are poisonous and yet we found a way to make them edible, and blowfish is supposed to be an insta-kill), and have ''eaten to extinction many animals bigger than us'' that were unlucky enough to first meet humans after we had perfected our hunting techniques (big animals that are still around were either lucky enough to see us perfecting our techniques and learned to fear us or lucky enough to live near better preys and have time to learn to fear us while we exterminated something else). Everything fearsome on this world, including [[BearsAreBadNews bears]], [[ThreateningShark sharks]], tigers, crocodile, and pretty much anything on this list, fear starving humans, because, with modern hunting techniques and weapons, the only reason they're still alive is that ''we learned restraint''.
* Armadillos; generally they'll flee from any humans by burrowing, and prefer to lock themselves in place if you try to root them from a surface it take effort to dig through, but most Armadillos carry ''leprosy'', which they're immune to. A single swipe on raw skin could very easily give you one of the most feared contagious diseases in world history.
* The [[PufferFish porcupine puffer]] is a friendly-looking curious fish that also happens to be a vicious predator. Yes, you read that right. Porcupine puffers (like all puffer fish) have teeth are formed into a beak-like shape that's razor sharp. Likewise, they have powerful jaws that allow them to crack open the shells of creatures like clams and snails. [[http://www.youtube.com/watch?v=6msgQFXOhrk Here's one eating a hermit crab.]]
** They're not short on defenses either. Like all puffers, they can inflate their bodies to intimidate predators, and they have the added bonus of being covered in sharp pointy spines (hence how they got their name). And, if those defenses don't work...Well, did we mention that their bodies contain a poison that's 1200 times deadlier than cyanide?
** Their smaller cousins, the Green-Spotted Puffer are like tiny adorable piranha when they're hungry. Don't believe us? [[http://www.youtube.com/watch?v=2KD_o1VnyRA Here's a pair of them (and a Figure "8" Puffer) eating a crayfish.]] [[AndIMustScream while it's still alive.]]
** PufferFish are also notoriously territorial, even the little ones, to the point where they'll attack any other fish in the same tank. Now, that may not seem like much, until you realize that they are known to attack fish much larger than themselves. There are many accounts of fish owners putting a larger fish in the same tank as the puffers only to check on the tank the next day and find the larger fish is dead. Turns out the larger fish died a slow agonizing death because the puffers would repeatedly attack and tear it to shreds.
* [[http://www.latimes.com/nation/shareitnow/la-sh-22-pound-house-cat-traps-family-20140311,0,7902156.story#axzz2vk8cD8mo This cat]] apparently went absolutely ballistic, started trying to attack everyone in the house, and was only eventually stopped when the police arrived and trapped it.
* Why has no one mentioned [[PricklyPorcupine porcupines]] yet? Most people assume that porcupines are just a bunch of pudgy, clumsy looking rodents who only managed to avoid being a predator's meal by virtue of being too spiky to eat. However, old-World porcupines will take the offensive by turning around and running towards persistent attackers with their spiny backsides, hoping to stab them. The Indian Crested Porcupine does this so effectively that brushes with predators like leopards and tigers often result in death or severe injury. The lucky ones that manage to survive often are forced to become man-eaters because of their injuries. It's for this reason that porcupines have very few predators.
* Australian magpies may seem like harmless songbirds, but they do have a reputation for attacking people who come near their nests.
* Silly as it may sound, there are such thing as [[http://en.wikipedia.org/wiki/Guard_llama guard llamas]]. Single llamas living with other livestock (including cattle and poultry) often become very protective of their charges. Unlike most domestic herbivores, llamas will go on the offensive and attack any predators that threaten the herd. As a result dogs and coyotes have been injured and even killed by llamas. A study done on the effectiveness of guard llamas and sheep found that average sheep losses dropped from 26 sheep per year to 8 sheep per year when the camelids were put into place. To the sheep ranchers, [[EverythingsBetterWithLlamas everything really is better with llamas]].
* Somewhat inverted with opossums. They look like giant rats and have [[MoreTeethThanTheOsmondFamily 50 teeth]] with big, sharp canines (especially the males), which they show off as defense with loud hissing, but they're usually quite docile. They're also much less likely than other wild mammals to carry rabies, due to their cooler body temperature and tough immune system.
* Many docile and adorable house pets that look totally cute and non-dangerous will go into a Killer Rabbit mode when they feel seriously threatened. A nice, cute hamster or an extremely friendly and docile pet rat can inflict some serious damage to its owner or anyone who gets close to it once it feels it's a LastStand situation ("a cornered rat bites the cat").
* The [[http://en.wikipedia.org/wiki/Sun_bear Sun Bear]] Is the smallest member of the bear family. They are also known to be [[BearsAreBadNews highly aggressive and attack humans]]
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