Most multi-headed creatures have separate consciousnesses in their different heads. But what about those creatures with multiple heads and faces but only a single consciousness? Then you get Peripheral Heads.
Peripheral Heads are extra heads on a character and/or creature that do not function as individual consciousnesses but are simply there to do the bidding of the main head. These are not "false heads" as seen on various species, but are true heads that have most of the requisite features except for brains. The heads may also Speak in Unison.
If the creature/character has multiple heads that usually agree on things but still each have a mind of their own, that's still Multiple Head Case rather than this trope.
Examples often fall under A Head at Each End, Belly Mouth, Extra Eyes, and Too Many Mouths. Compare Organ Autonomy and Cognizant Limbs. Subtrope of Spare Body Parts. Aversions fall under Multiple Head Case.
Examples:
- Beast Wars Neo: Magmatron's alt-mode is actually three different animals, a Giganotosaurus, an Elasmosaurus, and a Quetzalcoatlus. While each have their own head, there's only one personality that controls all three and can speak through any of the three mouths. The same goes for his third mode, which has them combine into a chimeric creature called Magmasaurus and again uses all three heads at the same time. In fact, all of his beast mode heads are peripheral heads: his real head is his robot mode head.
- Chainsaw Man: Multiple Devils have multiple heads and/or faces as part of their design, such as the Curse Devil, the Darkness Devil, and the Gun Devil. However, for all intents and purposes, each of them acts as a single being.
- Claymore: During the Final Battle, Priscilla devours Cassandra and spawns several copies of Cassandra's head (attached to Priscilla's rapidly mutated body by long prehensile necks) to attack the heroines. None of these heads house Cassandra's (still intact) consciousness, and they are instead little more than attack drones controlled by Priscilla's own will.
- Delicious in Dungeon: Discussed and played straight in the anime adaptation in "Roast Basilisk", where the group hunts a basilisk — which in this case is a chicken with a snake for a tail (or, rather, the other way around). The party comments that even though the basilisk has two heads, they're both part of the same being and it can't process stimuli from both ends at the same time. The manga states that the basilisk has two brains and that striking from both ends confuses the animal, which suggests a subversion but isn't entirely inconsistent with this trope.
- Transformers: Cybertron: Scourge, leader of the Jungle Planet, transforms into a three-headed dragon. The two side heads function purely as flame throwers.
- Transformers: Robots in Disguise: One of Megatron's many alternate modes is a two-headed dragon. Both heads speak in unison with the same voice.
- Yu-Gi-Oh!: Blue-Eyes Ultimate Dragon, as the fusion of three Blue-Eyes White Dragons, is a triple-headed terror. While this trope isn't evident in its behavior (most Monsters don't express much in the way of personality), Blue-Eyes is confirmed to have the soul of a woman, presumably shared with the three copies of the card, meaning that the Ultimate Dragon only has a singular soul.
- Godzilla:
- King Ghidorah, in most incarnations except for the MonsterVerse and Godzilland, has three full-sized heads that nonetheless all act as part of the same being.
- The Big G himself in Shin Godzilla has a small vestigial head at the end of his tail. It does not act as its own individual consciousness and is mostly used as a peripheral weapon. It seems to be a reproductive organ as well, as multiple skeletons are seen emerging out of the tip of the tail at the end of the movie, thus possibly explaining why an extra head was there in the first place.
- Little Shop of Horrors: In his final form, Audrey II grows buds that accompany him during his Villain Song, but they do not seem to act independently otherwise.
- The Troll Hunter: Some trolls grow extra heads as they age. It's explicitly stated that the new heads do little else other than act as extra noses, eyes, and ears.
- A Dearth of Choice: Timmy the baby Bone Hydra has five heads, with the central one seeming to act as the "main" head (given how it's given the priority for better skulls when they collect new ones) with no indication that the other heads are sentient in any way.
- Exordia: The khai are eight-headed snake people, but they only have a single brain, located in the hump where all those necks meet. Their heads are fairly autonomous appendages akin to octopus tentacles and have complex enough instincts and reflexes to have individual 'personalities', but there's ultimately only one mind at work behind all of them.
- The Hitchhiker's Guide to the Galaxy: This is usually the case with Zaphod Beeblebrox, having two heads is so rarely relevant that it approaches Informed Attribute. However this does depend on the writer, some adaptations give the heads more distinct personalities, while the sixth book by Eoin Colfer has one of the heads detached and take on a new identity and personality.
- Known Space: Pierson's Puppeteers have two heads and can hold two conversations at once, but both heads are controlled by a single consciousness from the creature's brain, which is located in a hump on their body.
- Dungeons & Dragons: Tiamat, the goddess of chromatic dragons, has five heads, one for each color of chromatic dragon. All five heads work in unison without conflict, she's a single goddess, not some sort of collective.
- Numenera: The octopi's Coral Cathedral is guarded by an artificially-created monster that resembles an eel with three heads. Only the central head has eyes and a brain; the other two are functionally more like limbs with mouths and esophagi.
- Shadowrun: Hydras have nine heads, but these only contain sensory organs and basic nerve ganglia. The real brain is at the base of the spine.
- Bayonetta series: Many of the Angels (and some of the Infernal Demons) have multiple heads and/or faces, but usually have a single mind each. Often, this manifests (at least in Angels) as a large beast having one or more marble human-like faces on its body. The Auditio Fortitudo is an exaggeration of this trope, having two dragon heads and an upside-down humanoid face on its chest that it uses to communicate and that controls the entire being.
- Fallout: Several mutated fauna sport two heads, both of which seem to work in unison to suggest they only share one functional brain, and named specimens are only given a single name rather than one for each head. They can sometimes (but rarely) even survive after having a single head blown off.
- Final Fantasy:
- Final Fantasy VII: Bizarro-Sephiroth is the second-to-last form that Big Bad Sephiroth assumes during the final fight, and resembles a giant, mutated version of himself with a smaller copy of himself coming out of its head, with neither one acting independently of the other.
- Final Fantasy VIII: Tri-Face is a monster that appears to have three heads, but the central head is the only one with any control over the body - the two side heads can bite and spit poison, but don't have any capacity for thought or consciousness.
- Helltaker: Cerberus takes it a step further by having three entirely separate bodies, but only one soul and one consciousness controlling all three. They refer to themselves as we, but are for all intents and purposes a single demon who collectively feels everything all three bodies feel at once. Apparently this can cause trouble when eating pancakes:
The Helltaker: If all three of you eat pancakes at the same time, does that make the pancakes triple delicious?
Cerberus: Whahoho! Hold up right there for a second! It's not as simple as you think! There are unique dangers involved! We could get stuck in an infinite loop of pleasure! Things would get out of control real fast... usually ends in bloodshed. - Mega Man Zero 3: This is played with by Tretista Kelverian, the Reploid boss based on Cerberus. His speeches give no indications that his extra heads have any mind of its own, not helping in that he's a Dumb Muscle. But in the backstory, it's said that he used to have 3 separate thought-circuits that helped him think more efficiently and fairly as part of his role as the Chief Judge of 8 Gentle Judges, before Dr. Weil reprogrammed him.
- Pokémon:
- Dusknoir has a true head that's small, gray, and featureless aside from a single eye, in addition to a face-like pattern on its chest and a Belly Mouth that can fire attacks. In some incarnations, it uses the Belly Mouth to speak. Dusknoir's head and "belly-face" are aspects of the same being and do not have separate minds.
- Hydreigon is a three-headed dragon that evolves from the two-headed Zweilous. However, unlike Zweilous' Multiple Head Case, Hydreigon's peripheral heads are much more simplistic, don't have brains, don't blink, and don't react to stimuli, as the Pokédex repeatedly hammers home that only the main head has a brain and is able to think. The peripheral heads do have fully-developed eyes and mouths, which it uses to aid the main head in combat. When interacting with it in the 3D games, it mostly uses its side heads as hands unless it's eating, in which case it will use all three of its mouths to ravenously devour its food.
- Guzzlord, a Dark/Dragon-type just like Hydreigon, has a small head on top of its body and a larger face on its chest with a Belly Mouth. It uses both faces to emote at the same time, but the true head houses its brain.
- Mr. Rime inexplicably has a clown-like face on its belly in addition to its normal face. Neither face acts independently of the other; it's said that the main head is mostly unexpressive, while the belly face is used to show its emotions.
- Girafarig is an example of Multiple Head Case, with a small head on its tail that acts on instinct and has a brain of its own. When it evolves into Farigiraf, the tail head becomes a "hood" of sorts over the main head, and both of its brains are connected via thick nerves. The brain waves of its two fused heads are now in sync, increasing its psychic powers.
- Hydreigon's Future Paradox counterpart, Iron Jugulis, zigzags this trope. While its secondary heads do emote, unlike Hydreigon, they're now also physically separate from the main body and can be fired as drones.
- Shin Megami Tensei: Satan's design introduced in Shin Megami Tensei IV: Apocalypse has seven heads — three draconic and four humanoid — but he only seems to speak through the center draconic head.
- Super Mario RPG: Exor, the living sword-ship, has a human-like skull on his pommel in addition to the large face on his guard. During his boss battle, each eye, his mouth, and said skull act as separate targets. Said skull is the main target in the battle, and is not an independent part of his body.
- World of Warcraft: The majority of two-headed ogres are portrayed as having separate personalities in each head. However, a small handful have two minds that operate in perfect unison, and these tend to be the most intelligent and accomplished of their kind. Imperator Mar'gok, the last of the ogre kings, is described as having two brains that work together just as easily as two legs.
- Yo-kai Watch: Slimamander, Eyedra, Mitsumata Nozuchi, and Mitsumata Mizuchi are all reptilian Yo-kai with three mouths that act as their own heads. An eye travels down their necks to swap between each head, and the head with the eye, usually the central one, is the one in charge. Later instalments make it much clearer they're vestigial as, when the characters appear in humanoid forms, the other heads are reduced to shoulder pads while the central head is the only one that remains. The only exception to this rule is Blasters, where they have additional eyes. This is because they are actually a Fusion Dance of three Yo-kai, creating a new Slimamander, rather than the original one with a single mind.
- Snaiad: Snaiadi animals have two "heads". The upper one, located where the head would be on an Earth animal, is actually the genitals, which have a large hinged "sheath" that in more developed animals is also used to fight and to tear apart and chew food; the eyes are also located here. The lower head, which projects from the chest, is a simple trunk that sucks up chewed material, although a few taxa have developed more advanced jaws while the upper head is only used for mating and sensory perception. Neither head houses a brain, as their brains are located in their chests.
- Beast Wars: Many Maximals and Predacons have their beast mode heads on some part of their bodies in robot mode, but the extra head does not act on its own. While Megatron treats his T. rex head/right hand as a Right-Hand Cat at one point and it seems to "react", this is an anomaly and can easily be explained as him putting on a puppet show for himself (this is the galactic overlord who owns a rubber duck, after all).
- Dungeons & Dragons (1983): Like her tabletop counterpart, Tiamat has five heads for fire, ice, lightning, acid and poison. However, her central fire head is depicted as larger than the rest and is the only one shown to speak, while the other heads appear to be purely accessory.
- Gravity Falls: The Multi-Bear has eight heads, though only the largest head on top is sapient and capable of speech, while the others just grunt and roar.
- Hercules: The Animated Series: Typhon has five heads. However, only his central head talks and emotes and makes expressions, while the other four smaller heads act more like his hands.
- Krapopolis: One episode features a hydra whose heads all share a hive mind and speak as a single personality from each of her different heads. She is also able to see and hear and speak through all her heads, allowing the citizens of the city to essentially use her as a low-tech fantasy version of the Internet (with all that implies).
- She-Ra: Princess of Power: Greater-Scope Villain Horde Prime is evidently an example of this, as he has a single personality and reportedly two heads, but since he's also The Faceless (always depicted lurking in an enormous black cloud) the exact details are unknown.
- SpongeBob SquarePants: "Move It or Lose It": Three-Headed Jake
is a fish with three heads. Given that SpongeBob refers to the fish as "he" and only has one name, Jake is a single fish with three heads rather than three separate fish with a single body.
- The Super Mario Bros. Super Show!: Tryclyde can speak through his central head, but not his other two heads, implying the latter two are peripheral heads. He is also referred to as "he" rather than "they."
- The Transformers: Hun-Gurrr, leader of the Terrorcons, transforms into a two-headed dragon-like monster. Both heads speak at the same time with the same voice (although the audio is not actually doubled). This contrasts with his subordinate Sinnertwin, a true Multiple Head Case whose heads are voiced by different actors and argue over who gets to eat their opponent.
- There is a distinction between real-life animals that have multiple faces and multiple heads. In most cases, the former category has both faces controlled by the same brain, and they will often act in tandem.

