Too Many Mouths

In the same way that having Extra Eyes in unusual places can be unnerving, a creature with extra mouths can also be horrific, in a different way. The mouth is the organ of consumption, so a creature can be given extra mouths to show that it is a ravenous, hungry monstrosity. A massive paunch and lack of other sensory organs will create the image of an organism with no intelligence or purpose other than to eat.

To enhance the effect of the mouths, they may be equipped with More Teeth Than the Osmond Family, or alternatively, might be gross and wide orifices with a thick tongue and smacking lips.

But there are many other ways to add mouths, and many places. They can be obvious or discrete, even hidden. They may even have special properties or powers. Their owner can be an Eldritch Abomination or a seemingly-normal human, or anything in between.

A Super Trope to Belly Mouth, Nested Mouths. Contrast No Mouth.

Anime and Manga

 * Deidara in Naruto has mouths on his palms. They spit out a plastic explosive that he uses to create exploding scupltures. It later turns out he also has one on his chest.
 * In The Slayers, Copy Rezo has mouths on his palms. These mouths are used to utter incantations, though, not to eat or bite.
 * Vampire Hunter D. The title character has an extra mouth in the palm of his left hand which can suck in large amounts of material at will. It has a mind of its own and can talk to D.
 * In the Fullmetal Alchemist manga, the true forms of Father and Pride are shadow tentacle monsters made up of eyes and mouths. Also Gluttony with his giant one down the middle.

Card Games

 * The All-Devouring Oni in Magic the Gathering's Kamigawa storyline was this taken to its logical extreme: a swarming cloud of mouths with dagger-like teeth.
 * Slifer the Sky Dragon from Yu-Gi-Oh (both the card game and the anime) has two mouths.

Comic Books

 * "The Corinthian" character from Neil Gaiman's comic book series The Sandman has mouths where his eyes should be.

Literature

 * In Ramsay Campbell's Cthulhu Mythos stories, when the Great Old One Y'golonac possesses a human body, the body has mouths in its palms.
 * Darren Shan's The Demonata has Artery, one of Lord Loss's familiar demons, who has mouths in his palms, with very sharp teeth in them.
 * In Wayne Barlowe's Expedition, the gigantic creatures called sea striders have mouths in the bottoms of their feet, allowing them to gulp down mouthfulls of the Amoebic Sea just by walking about.
 * Betelgeusians in the Star Trek Novel Verse have two mouths; a beak-like one for speaking with, and a toothy one for eating with. As might be apparent from the description, they're not intended to be frightening or disgusting, just alien.

Live Action TV

 * In the original Battlestar Galactica Pilot Movie, there was a female singing group, each of whose members had four eyes and two mouths (and apparently they could each sing two different notes).
 * Rassets/Mandilok, of Hyakujuu Sentai Gaoranger/Power Rangers Wild Force, literally embodies this trope.

Mythology

 * The Japanese Youkai Futaguchi Onna (two-mouthed woman) appears as a normal woman with a huge, costantly hungry mouth on the back of her head. Usually the normal mouth rarely eats, while the other one often gorge itself on anything in sight and can use the hair as tentacles.

Tabletop RPG

 * Dungeons and Dragons. The Gibbering Mouther monster was a human-sized amoeboid life form covered with eyes and mouths. It used the mouths to bite its victims.
 * Villains and Vigilantes adventure Devil's Domain. Abomination demons had a malevolent face on their chest, which included a large mouth.
 * Call of Cthulhu:
 * Dreamlands. The Maws of Pandemonium spell caused the victim's body to sprout a red-lipped mouth that gibbered and moaned as it drained the victim's magic points. When the victim became unconscious, the mouth fell silent, but started howling again two to 12 hours later.
 * When the Great Old One Y'golonac possesses a human body, the body has mouths in its palms the same as in the original Ramsay Campbell stories.
 * Aku-Shin Kage, one of the masks of Nyarlathotep. Dressed in the traditional armor of a samurai, where its face should be is covered in mouths instead.

Video Games

 * In Spore, the creature creator allows many mouths to be affixed to a given creature, though they seldom render any actual benefit to the creature.
 * Yogg-Saron, "The Beast with 1,000 Maws" from World of Warcraft, who has mouths in place of his nostrils, eyes, and a few others. Those are just the ones you can see.
 * The monsters in Dantes Inferno, appropriately called Gluttons and appearing in the circle of Gluttony, have mouths for hands. The boss of Gluttony, Cerberus, is a giant toad-like creature with three worm-like tongues, all decorated with extra mouths.

Web Comics

 * Demon Eater has the titular character join the Human Club, those creatues of his world who for one reason or another wish to emulate humans, but none does it well. The one named Venus has extra eyes and mouths so that she has faces on her left and right profiles.
 * The Expy of Y'golonac (see Literature) in The Unspeakable Vault of Doom loves to prank other gods by shaking their hands and biting them off.

Western Animation

 * In The Spectacular Spider Man, Venom can manifest a large mouth in the center of his costume, and can talk through it.
 * Gilda Gossip, a gossipy alien in Galaxy High, voiced by Nancy Cartwright, had multiple mouths growing out of antennae on her head.
 * On Buzz Lightyear of Star Command, the president of the galaxy has two mouths, one atop the other. Her whole race has this trait, but she's the most frequently seen.

Real Life

 * Mistaken for played straight in one case: The Cambrian sea creature Hallucigenia was first reconstructed with seven tentacles on its back, each bearing a small, beak-like mouth. But as Science Marches On, it turned out that said tentacles were actually paired legs and the beaks their claws.
 * Up to date, there was still no Hallucigenia fossil found that shows where the creature's mouth was really located.