Distinguishing Mark

The physical version of Something Only They Would Say, where a character is identified by an unusual body deformity or trait, like a mole or birthmark. Bonus points if the mark is in a place that would be embarrassing/forbidden to show in public.

See also Scars Are Forever. For a Distinguishing Mark that marks the Chosen One, see Birthmark of Destiny.

Anime and Manga
"Security Guard: "With that beard and mask, anyone could look like him!""
 * Subverted in Mermaid Melody Pichi Pichi Pitch, when Tarou notices a mermaid with Rapunzel Hair and is sure it must be Sara. It's not. All mermaids have long hair, and they otherwise looked nothing alike.
 * In Chrono Crusade, Chrono's missing horns are so prominent that he's known as "Chrono of the Broken Horn" to some of the other demons. And, of course, Satella is searching for a demon without horns...
 * In Haruhi Suzumiya, Mikuru's mole on her left breast is the usual thing Kyon looks for when he wants to see if it's the "real" Mikuru. In the novels, Kyon once asked her to show it (to which she replied with a punch) and another time realized it was not her because of it.
 * In Lucky Star, Konata looks identical to her mother, except for a birthmark under her eye (and her ahoge).
 * Jacuzzi Splot from Baccano! is often immediately identified by the blue, oddly-shaped sword tattoo on his face - unfortunate for him, considering that he's got a large bounty on his head and more than a few enemies with an axe to grind.
 * A meta-example in Higurashi no Naku Koro ni: the identity of the corpse discovered at the beginning of Curse Killing Chapter is never revealed, but an astute-eyed viewer can figure it out for themselves if they spot the Distinguishing Mark --.
 * The easiest way to identify a HiME is a fireball-shaped Power Tattoo on their body. It's in a different spot for each girl - Mai's is on her right breast, Natsuki's is on her lower back, etc.
 * Kotetsu T. Kaburagi/Wild Tiger from Tiger and Bunny has a rather distinctive-looking goatee. In fact, it's so distinctive that it's implied that many people don't bother to remember what the rest of him looks like.


 * In Fullmetal Alchemist Maria Ross has a mole under her eye.
 * In Inuyasha, the titular character has fuzzy, white dog ears on top of his head (not floppy ears like most dogs, more like the Shibi Inu breed.) This marks his heritage as an inu-hanyou - half human, half dog-demon. He also his golden eyes with cat-like pupils, like his father.
 * Most of the demons in the series show certain traits that tell them apart from humans, even when in humanoid form. These include pointed, elf-like ears, unusual coloration in their eyes and hair, and (sometimes) claws and fangs. If their true form has a tail, that will often be visible, since it apparently takes a lot of power to hide it.
 * In Shippou’s case, hiding the tail is often a problem when he disguises himself using his fox-magic. (Shippou is a very young kitsune-youkai - fox demon. In Japanese folklore, foxes were said to be great tricksters, and the masters of disguise. Being so inexperienced, Shippou still isn’t very good at shapeshifting, but he’s getting better.)

Comic Books

 * Princess Sally has a "royal birthmark". Espio knows where it is.

Film
"Coroner: "Mrs. Lefferts, does your daughter have any distinguishing marks?" Mrs. Lefferts: "She has a birthmark on her hip. It's her. My baby!""
 * The Marx Brothers movie Animal Crackers identifies Roscoe W. Chandler as Abie the fish peddler with a large birthmark on his arm. Chico's and Harpo's characters later steal a wide array of his possessions - Harpo gets the birthmark.
 * In The Princess Bride, Count Rugen is identified by his sixth finger on his right hand.
 * There's a royal birthmark (the Purple Pimpernel) on the royal posterior of the true heir to the throne in The Court Jester. Danny Kaye's character gets to show the infant's bottom to everyone to gain their reverence.
 * L.A. Confidential: A mother cannot initially ID her daughter in the morgue. The Coroner prompts her with Detective Lieutenant Exley and Officer Bud White hanging on her every word:


 * The scene won the 1998 Skinny Award for "Best birthmark used to further the plot".

General
""Just pretend you're a box of cereal and I'm scanning your barcode.""
 * The barcode (which may be a tattoo but probably isn't) is often used as a sci-fi variation on the birthmark.

Literature

 * The Goosebumps book "My Hairiest Adventure" has a character with one blue eye and one green eye -- which turns out to be important after.
 * The Dragonlords of Joanne Bertrin's novels all have a distinguishing physical mark (birthmark, odd eyes, dwarfism, albinism) which indicates their Dragon natures. One of the clues that a young woman is not really a Dragon is that her mark can easily be hidden.
 * Harry Potter
 * Harry Potter and The Prisoner of Azkaban uses the missing toe on Scabbers's front paw thusly.
 * In Harry Potter and The Deathly Hallows, Lucius Malfoy uses the scar on Harry's forehead to identify him, since Harry's face has been disfigured by Hermione's jinx.
 * All of the Death Eaters have a Dark Mark branded on their arms.
 * Hannibal used to have six fingers on one hand, more specifically a second middle finger. He has it surgically removed after Silence, but of course he retains his maroon eyes.
 * The Sylver family line in Welkin Weasels all have a facial birthmark shaped like a lightning bolt.
 * Conan the Barbarian:
 * In Jewels of Gwahlur, Conan identifies a slave girl imposter by a birthmark.
 * In A Witch Shall Be Born, the witch can be identified by her birthmark.
 * In E. Nesbit's Five Children and It, after the children foolishly wish that everyone would want their little brother and then have to chase after everyone who kidnaps him, one character claims him as his long-lost son because he doesn't have a birthmark.
 * Edward Rutherfurd uses this trope a lot to distinguish between the families in his Generational Saga novels, variously giving them characteristics such as long toes, waddling gaits, or oversized noses. Played with a bit in London, in which the Ducket/Dogget line has three such traits: natural Skunk Stripe hair (both sexes), partially-webbed fingers (several of the males), or obesity that's probably linked to hypothyroidism (a few of the females).
 * In the Judge Dee mystery The Chinese Maze Murders a father identifies his daughter's headless body by a burn on the arm that she got when she was just a toddler.
 * The heirs to the throne of Riva in the Belgariad have a white mark on their palms, burned into their bloodline when Riva Iron-Grip carried the Orb of Aldur.

Live-Action TV

 * The Hero Rohan in The Mystic Knights of Tir Na Nog has a birthmark called the Mark of Destiny that his druid mentor and foster father takes as a sign proclaiming him to be The Chosen One. He's right...but the mark isn't unique to Rohan.
 * Played for Laughs on ''Monk. In Mr. Monk Takes On Manhattan, Monk recognizes a tiny mole on the perps ear. He then spends an absurd amount of time describing the ear to a sketch artist. Later, when interviewing a suspect, Monk tries to get a peak at his ear.

Opera

 * Parodied in the Gilbert and Sullivan one-act opera Cox and Box, in which Box declares that Cox must be his long-lost brother because he doesn't have a birthmark on his arm.

Video Games

 * Professor Layton and the Curious Village: Flora Reinhold's disappearing-reappearing birthmark is the final clue Layton needs to solve the mystery of St. Mystere.
 * In King's Quest III, the way Gwydion proves he's is by showing Princess Rosella a birthmark he has in a rather embarrassing place.
 * In several The Legend of Zelda games, the mark of the Triforce (see the featured image on the Rule of Three page) appears on the hands of three individuals. Ganondorf has the Triforce of Power, Princess Zelda has the Triforce of Wisdom, and Link has the Triforce of Courage. Each piece of the Triforce is represented by a different triangle - Power is on top, Wisdom is on the bottom left, and Courage is on the bottom right.
 * In The Legend of Zelda Twilight Princess, Link starts out with the Birthmark of Destiny on his left hand (right in the Wii version). It’s also visible in his wolf form.

Web Comics

 * Nathan Hale in The Dreamer has a powder burn on his forehead and a mole on his neck.

Web Original

 * Sailor Nothing: Himei sports a black eye in Chapter 2; as she turns out, she can't Clark Kent her way around it.

Western Animation

 * G.I. Joe: The difference between the mirror image Tomax and Xamot? Xomat has a scar on his left cheek.