Attack Animal

Any creature which has been trained specifically to fight alongside its handler, like an attack dog or equivalent.

Generally speaking, in order to qualify as an attack animal the creature must:


 * Not act (or at least it must not be supposed to act) without explicit instructions from its handler beyond a normal routine. This usually entails something with animal level intelligence which can be trained to obey. Sapient creatures can count if they still fit this criteria (that is they're forced to obey, choosing to because of Undying Loyalty or because they're being paid isn't an example).
 * They must be acting at the command of their handler (it's not enough for someone to throw their victim into a cage full of lions, they have to be able to make the lions attack them).
 * The "creature" does not technically need to be an animal (semi-intelligent drones or golems, artificial biological constructs or magical, elemental beings are all fair game).
 * Not be sent out to act on their own (like when summoning a bigger fish), since they're essentially a weapon, not a character (a good analogy would be that you send out soldiers armed with swords, not swords on their own).

This trope is likely derived from domestic animals which were used for their attack abilities (dogs being the most obvious). See the Real Life section for more details. Using a "weapon" like this often implies that a character is either Closer to Earth and generally an all around good person who animals trust, a genius (possibly mad) who can create or control such things or evil, by virtue of "enslaving" them.

The Weapon of Choice for The Beast Master and the Nature Hero (although they might as easily avert this trope by making them actual characters). When everyone uses these and only has them attack one another then you're almost certainly in a Mons series. Examples of this trope are often a Weaponized Animal. Contrast the Cool Pet, Animal Companion and Robot Buddy, who are usually characters in their own right rather than just weapons. If they're picked up and used as a weapon see Equippable Ally. Super-Trope to; War Elephants, Angry Guard Dog and (if such a "weapon" serves as the villain's henchman) Right-Hand Attack Dog. A subtrope of Living Weapon. Sister trope to Animal Assassin.

Examples;

Anime and Manga

 * In One Piece, Doctor Vegapunk has apparently done extensive research into the nature and abilities of Devil Fruits, even making inanimate objects able to eat them. There have been a gun and a sword who have respectively eaten the Inu-Inu (Dog-Dog) Fruit: Model Dachshund and Zou-Zou (Elephant-Elephant) Devil Fruits respectively, resulting in a dog that sneezed explosive baseballs and an elephant that could transform into a sword. Of course, this being One Piece, it basically turns out just how you would expect.
 * The Jinchuuriki from Naruto are essentially this, or were at least meant to be. Yes, even Naruto himself. I wouldn't call them that though, they may not take it well.
 * Among other things, Humanforms and the titular Xam'd in Xam'd: Lost Memories.
 * Ginga: Nagareboshi Gin: Bear hunting dogs
 * Ginga: Nagareboshi Gin: Bear hunting dogs

Film

 * Word of God states that the Xenomorphs from Aliens are these.

Literature

 * JRR Tolkien liked this trope. Lord of the Rings contains trolls, mûmakil, wargs, fell beasts, etc. Apparently Morgoth originally bred Smaug's ancestors for use as living weapons as well.
 * Wheel of Time had Trollocs, Myrddraal, Darkhounds, Gholam, Draghkar, and Jumara (collectively called Shadowspawn) all created by Aginor to be living weapons of the side of the Dark One.
 * There are also trained war horses, which are described as being just as deadly as their riders.
 * The Heralds of Valdemar series has the Shin'a'in battlesteeds. Unlike your average warhorse, these have been bred over centuries to be the ultimate fighting mount (possibly with some magic help at the beginning). Smart, obedient, and capable of distinguishing and killing enemies without any direction, they make a deadlier team with a human than another human would. They're also good at tasks such as guarding camps and equipment, finding water in the forest, and carrying injured riders to get help. What they aren't good at is being pretty; looks had no priority in the breeding program and the steeds resemble roughly-carved horse-shaped granite.
 * Both Arthur C. Clarke and Stephen Baxter's works feature a plant designed to grow on the Moon, taking all its necessities from the lunar soil, and to germinate by firing its seed as a projectile. In Clarke's short story,, with obvious results. In Baxter's novel Space, a similar creation is transplanted to , where it and plays the central role in Humanity's Crowning Moment of Awesome against the alien invaders.
 * The Leviathan series utilizes this as one of the main motivators of the plot itself. The entire Allied side (Darwinists) use genetically-engineered super animals as war machines. Not to mention the living airship...
 * In the web-novel Domina, the "fey" use bio-engineered monsters as weapons. They're too crazy to use them effectively, though, so they usually just throw a few out when they're bored.
 * Robert Heinlein's Tunnel in the Sky. When Johann Braun goes on his survival test, he takes along his pet, a big, lean, heavily muscled boxer dog named Thor with unfriendly eyes. Interestingly, they're both killed only minutes into the test.
 * Andre Norton's Beastmaster novels, such as The Beast Master and Lord of Thunder. Hosteen Storm was a Beastmaster who could telepathically command several animals. One of them was a sandcat named Surra who was highly effective in battle.
 * In the Sherlock Holmes novel The Hound of the Baskervilles a hound is dressed up to look like the Hound of legend and is used to kill old Sir Baskerville & attempted to kill the new young Sir Baskerville.
 * Alan Dean Foster's Humanx Commonwealth stories starring Pip and Flinx. Flinx has a pet Alaspinian minidragon named Pip. Pip can spit an acidic poison into opponent's eyes to blind and kill them and can also amplify Flinx's psionic powers.
 * In The Dark Tower, main character Roland must defeat his instructor in single combat and can only bring one weapon to the duel. His weapon turns out to be his hawk, David.

Live-Action TV

 * In Firefly, River Tam was conditioned by the Academy to be a psychic assassin apparently controlled by imbedded subliminal codes. In Serenity she is explicitly called a "living weapon."
 * Subverted in Frasier. Martin has been staring at photos from an unsolved murder years ago. When he goes to take a break, Frasier glances at them and concludes a trained monkey was used to kill the victim. When Martin solves the case, Frasier assumes he was right about the monkey, but we learn it was a crooked cop.
 * In the Buffy the Vampire Slayer episode "The Prom", Andrew has hellhounds, which his brother Tucker bred and trained to attack the people at said dance. Not to mention, as Andrew will remind you, he trained flying demon monkeys to attack the school play.
 * Highlander had an episode with an immortal named Kanis, who used his pack of dogs to bring down his quarry. Duncan managed to throw a wrench in things when Kanis tried it on him, using a female dog in heat.
 * In an episode of Bones a dog is used by its owner to kill a vet looking into dog fighting. Booth & Brennan are quite clear that a person killed him using the dog as a weapon.
 * Alex's landlord, Jim, in the Doctor Who episode "Night Terrors" has a mean dog which he uses to threaten Alex.

Newspaper Comics

 * Very early in the life of Garfield, Jon tried to train the titular feline into an attack cat. He only succeeded in getting himself mauled.

Tabletop Games

 * Warhammer 40000's Tyranids are an entire species created to serve as weaponry, controlled by other species, which are seen as the same family as the weapons.
 * Also from Warhammer 40000 are the Orks. They are believed to be created by a group of beings called Brain Boyz as a weapon against the Necrons. They are quite effective weapons against them, unfortunately the same is true of everyone else. Of course technically the Brain Boyz were themselves created to be their controllers by the Old Ones.
 * Squigs are small, aggressive critters that Orks frequently keep as pets and train to attack people on command. The largest of all squigs is the massive Sqiggoth, which grows to be as big as a Baneblade tank.
 * Forgotten Realms prehistory says wyverns were created as weapons by Aearee (ancient bird-like creatures). Local Precursors are called "Creator Races" for a reason.
 * Wizards constantly try to customize some or other Hybrid Monster or The Undead for that purpose, though it rarely ends well. Akhlaur has "cat-man warrior" project, for example.
 * In Dungeons and Dragons, early editions allowed PCs to buy war dogs that would fight alongside the character. Since they were almost as effective in combat as a 1st level character, they could greatly increase a party's chance of survival at low levels.
 * Stormbringer Companion supplement, "Sea Battle at Melnibone" solo adventure. One of the opponents Elric faces during the battle is a sea captain who has a war hound of Chalal fighting at his side.
 * Mongoose Publishing's Starship Troopers - The Roleplaying Game. Neodogs have cybernetically enhanced teeth and jaws, allowing them to enter combat alongside their handlers. In the original Robert Heinlein Starship Troopers novel, neodogs did not have such augmentations and were used for intelligence gathering, not fighting.
 * Hordes pits two warlocks and their armies against each other. Warlocks come in many flavors, but all share the ability to direct and give orders to their warbeasts, ranging from bipedal War Elephants and lightning-fast warpwolves to monstrous dragonspawns.

Toys

 * Bionicle: The Order of Mata Nui used trained Energy Hounds, most notably one in Mahri Nui named Spinax. Also in Mahri Nui, Toa Jaller had a Hahnah crab that, at least in his toy set, was equipped with a gatling cannon for him.

Video Games

 * Fina from Skies of Arcadia uses her pet (a creature called Cupil) as a weapon in precisely this manner.
 * The majority of monsters in the Resident Evil were created to be these. Although the ones that could follow orders had an alarming tendency to become...less controlled.
 * Similarly The Virus in Prototype, but this is more of a subversion, as the scientists of Blackwatch tried this and had it turn on them . The slavering zombies and various hideous flesh-beasts created when the virus finds human carriers do serve quite well as weapons, whether you prefer quantity or style, but exactly beings in the world are capable of controlling its spread and the creatures created, and there's nothing on Earth that's going to control them.
 * In Cave Story, a mimiga who eats one of the red flowers would grow exponentially larger, stronger, and more resilient. They then lose their minds and normally go uncontrollably berserk, but a person who wears the Demon Crown is capable of controlling them and making them fight at his side.
 * In Blaz Blue, the Kaka clan (and by extension Taokaka, one of the playable characters). They were created from  to combat the Black Beast almost 100 years earlier, can only reproduce (asexually) if there are less than 100 of them and can process Seifer naturally and use it to manifest glowing energy claws.
 * Rachel Alucard has a frog called George XIII hop towards her opponent and electrocute them as a ranged attack.
 * When Hazama created Mu-12, he more or less wanted her for this. Even referring to her as his "sword".
 * Lambda-11 is treated this way by Kokenoe (although she feels bad about turning her into an Empty Shell for this purpose). Tager might also count, but he's sufficiently loyal the issue of whether Kokenoe can force him to obey hasn't come up.
 * The eponymous creatures from Metroid, are more or less weaponized space-jellyfish. The problem is that no one seems to be able to control them too well. The only being capable of it was Mother Brain, and even then it wasn't complete. This didn't stop the Space Pirates from trying, of course.
 * As mentioned above the Zerg race from Starcraft are pretty much the same story as the Tyranids of Warhammer.
 * Hunter Pets in World of Warcraft. Warlocks and Deathknights have pets too, but they are either demonic or undead.
 * The Zuul in Sword of the Stars were originally created as weapons by the Suul'ka against a Morrigi colony. They were especially designed to be ravenous and fast-multiplying in order to quickly kill and consume all living things on the planet and die off. Unfortunately, the Zuul prove themselves masters at Mind Rape, allowing them to quickly learn the secrets of the target population, build spaceships, and escape into the universe. They are also extremely devious (at least, the males are; the females are mindless brutes; all by design).
 * In Ace Attorney Investigations 2, the blind assassin Ryoken Houinbo trained his guide dog to kill, to the point where it's considered one of his trademark weapons.
 * In Minecraft, once you tame a wolf by feeding it, it will follow you unless you command it to sit, and it will attack mobs that attack you.
 * Dragon Age has Mabari War Dogs; Highly trained and highly loyal attack dogs in use by the nobles and army of Ferelden.
 * Command & Conquer: Red Alert 3 has armored war bears as units, inspired by a Real Life bear namedWojtek.
 * Red Alert 2 had German Shepherds and Siberian Huskies as attack dogs. The same series gave us the Tesla Ants.
 * Final Fantasy VI and Final Fantasy VIII have characters (Shadow in VI and Rinoa in VIII) who use dogs trained to attack enemies.
 * In Final Fantasy X, the Aeon Yojimbo fights alongside his attack dog Daigoro.

Web Comics
"Buck: You don't look very dangerous.
 * Buck Godot: Zap Gun for Hire had Beemahs, Armless Biped created by Zmouf as spies and assassins. They weren't autonomous, but eventually found a new master, at which point Zmouf quickly became extinct. Beemahs were outlawed and supposedly extinct themselves, though.

Beemah: ZZOWWT!"

Western Animation

 * He Man and The Masters of The Universe. Battle Cat is this to Prince Adam, helping to fight his enemies.

Real Life

 * Besides dogs, many warhorses were like this, trained to bite, kick, or stomp at their rider's command.
 * In Britain, there is a stereotype associated with "chavs" of them owning vicious dogs which they use to threaten people with.
 * War Elephants
 * In India, this was taken a step further by amputating the tusk tips and replacing them with huge knives.
 * In Ancient Egypt they did this with trained cheetah and sometimes other big cats.