You Look Like You've Seen a Ghost

"Random Guy: What's the matter? You look like you've seen a ghost! Random Guy #2: (points to Martha) I just did! Look!"

- Half Magic

A Sub-Trope of Literal Metaphor. It started as nothing more than a simple simile in the real world to describe a look of utter shock, surprise, and/or fright. But at some point, no one knows quite when and no one knows quite where, some genius realized characters in fiction who really have seen a ghost would... look like they've just seen a ghost. Ergo, when characters enter screaming and running from a ghost (or any supernatural creature that would frighten your average Muggle), it is customary for a Genre Blind character to say in complete jest, "What's wrong with you? You look like you've seen a ghost." Alternatively, the line may be said mockingly by the 'ghost' - whether they're literally a ghost, some other kind of undead, or merely wrongly believed to be dead - themselves.

Parodied and subverted like crazy these days, but the mystery abounds as to why this isn't a Dead Horse Trope yet. A Sub-Trope of I Was Just Joking.

Anime and Manga

 * Ryo uses this exact wording in the FAKE manga when Dee and Bikky race into his room after seeing a young girl's ghost in the mansion they're staying in. When Dee and Bikky insist that they did, Ryo's hidden Deadpan Snarker tendencies come out and he says coolly, "There are no such thing as ghosts."
 * With the main characters appearing as spirits and investigating paranormal events in Ghost Hound, the characters and spirits around them often get this reaction.
 * Line used by Luck Gandor in Baccano when speaking to a man involved in his "ventilation".
 * One of Tetsuo's lackeys asks a different corrupt follower what's wrong and makes this remark when he first sees Tetsuo's horrifically mutated arm in the Akira manga.

Fanfic

 * This line accompanies The Reveal of the villain's identity in Chapter 12 of The Mad Scientist Wars.

Film

 * Wild Wild West? Has it been mentioned yet? (Loveless says it after getting out of the Abe Lincoln Cake)
 * Used by Lady Van Tassel in Tim Burton's Sleepy Hollow.
 * In the third Back to The Future movie, Doc says this to Marty after Marty finds Doc's grave.
 * The Star Trek V had Kirk say this to Spock when he'd seen his long lost half-brother. "Perhaps I have, Captain."

Literature
"McNeil was just standing in the doorway, looking as if he had seen a ghost. The trite metaphor frashed into Grant's mind instantly. He did not know for a moment how near the truth it was. In a sense McNeil had seen a ghost -- the most terrifying of all ghosts -- his own."
 * Spoofed in a Ghost Twins book when one of the titular twins returns from an encounter with another, yet more mysterious, ghost her brother asks if she saw a ghost, to which she gives him an odd look and says, "I'm looking at one." Moments later, she confirms his suspicions.
 * In Dan Abnett's Gaunt's Ghosts novel Sabbat Martyr, after a miraclous cure, the cured Ghost tells the doctor checking him that she should sit down, she looks like she's seen a ghost. She sits and laughs very hard.
 * Rather more obvious as the Tanith First-and-Only are called the Ghosts due to their preturnatural ability to simply disappear, especially the scouts. even calls Mkoll sidthe, which means... ghost.
 * The ghost of Herald-Mage Vanyel says this very cheerfully in Winds of Fury after interfering with a teleport (which was supposedly impossible) to bring the main characters to the Forest of Sorrows instead of where they wanted to go. Vanyel has been dead for about 600 years at this point.
 * Played with in Arthur C. Clarke's story "Breaking Strain", in describing one astronaut's reaction to discovering that a meteor has punctured their reserve tank, leaving insufficient oxygen to reach their destination:

Live Action TV
": What's the matter with you two? You look like you've seen a ghost."
 * Are You Afraid of the Dark?? has actually used this multiple times:
 * In The Tale of Old Man Corcoran, the new boys in the neighborhood realize that the kids who have been telling them ghost stories about the old gravedigger.

"Grandpa: What's the matter with you two? You look like you've seen a ghost... Friend: Bingo! Granddaughter: We did!"
 * In The Tale of the Room For Rent, the two girls see their archetypal-creepy-old-woman-psychic-inclined next door neighbor summon a ghost that descends from the ceiling and walks by them right through the wall. They run screaming into the one girl's grandfather's house.

"Sam: You look like you've... well, I was going to say you look like you've seen a ghost, but you'd probably be stoked."
 * Played straight in the next to last episode of The Omega Factor after Tom seems to see apparitions of.
 * A usual Pun of Doubting Dave's on Mystery Hunters.
 * On Covert Affairs, Jai says this to Annie when she realizes that
 * On Supernatural, the Winchester brothers say this to Bela Talbot, after she sees a ghost ship captained by an angry ghost who's going to come back a few hours later and kill her.
 * Used again in "A Little Slice of Kevin" at the start.

Music

 * One of the lyrics from "Sometime Around Midnight" by the Airborne Toxic Event, said by the singer's friends to him after he encounters his ex in a bar.

Video Games

 * Lampshaded in World of Warcraft. Upon turning in a quest dealing with the ghost/spirit/essence of the Big Bad's innocence, Thassarian says to the player "What's the matter? You look like you've seen a ghost... Not that that would be all that unusual in these parts now that I think about it..." Also worth pointing out Thassarian himself is among the undead, albit a Death Knight, not a ghost.
 * This is among the final lines of Mystery Case Files: 13th Skull, when two Muggle NPCs find the Master Detective lying on her back in the Louisiana swamp.

Webcomics

 * In Devon Monk's Allie Beckstrom novel Magic in the Blood, after her father starts to haunt her.

Web Original

 * In Episode 1 of The Dr. Steel Show, Doctor Steel sees a ghostly vision of a magical transforming toy ("Winky") hovering about his lab, but it disappears into an air duct before he can get a Polaroid snapshot of it. Slightly inverted as he was more awed by it than scared.

Western Animation
"Danny: (to Tucker and Sam) Guys, what's wrong? You look like you've seen a ghost, or... something really scary that we don't see every single day."
 * Spoofed in an episode of Danny Phantom:


 * Happens all the time in Scooby Doo. Usually followed by the second person opening the door or what not, not seeing anything, then Scooby or Shaggy opening the door again, and seeing the ghost... and then everyone else seeing it the third time... cue Chase Scene.
 * In Transformers Animated, Starscream says this to Megatron after coming Back From the Dead. May also be a Shout-Out to the ghost Starscream episodes of some past series. This time, Starscream's not a ghost, just.
 * In Ben 10 episode 24, Ghostfreak has just gotten loose from the Omnitrix. Ben's grandfather, not knowing this, goes up to Ben and says the phrase.