Our hero is spending a quiet moment with a loved one. They enjoy some relaxing conversation, and maybe even take their companion into a tender embrace. Then, the door opens (or, alternatively, the phone rings) to reveal that the loved one is actually some distance away from them, and has been for some time. Cue the dawning moment of realization as our hero slowly looks back to the person right next to them...
Basically, some ghost, ghoul, or other evil creepy has decided to pose (using disguise, darkness, or some other subterfuge) as a friendly character. Whether it's for a specific reason or purely to freak out the protagonist (and the audience) we cannot be sure. In some instances, the disguised villain vanishes unnoticed upon the intrusion of the character they are impersonating, and the audience never sees their face. However, in most modern horror films, we are treated to a sudden shot of the monster in all its freaky glory, accompanied by a good, old-fashioned Scare Chord. Note that the threatening presence will remain hidden up until the hero discovers the deception (compare Gravity Is a Harsh Mistress).
- An example in The Haunting, taken directly from the source material: in bed, Eleanor clings tightly to Theodora's hand as sinister sounds emerge from the darkness in their room. Suddenly, the lights go on, and Eleanor sees Theodora sitting up in her own bed on the other side of the room. She has clearly not been anywhere near Eleanor for some time.
Eleanor: God...God...whose hand was I holding?
- The scene in Dark Water where Yoshimi and the audience thinks she is embracing Ikuko in the elevator... only to see Ikuko enter the hallway.
- The scene in The Orphanage where Laura feels her husband get into bed with her, and speaks to him for several minutes...before seeing him emerge from the bathroom.
- Scooby-Doo 2: Monsters Unleashed, as Scooby and Shaggy barricade a door against the Black Knight Ghost, Shaggy is handed armor pieces, presumably by Scooby. However, Shaggy then notices that Scooby is on his other side. The one passing armor to him was the Black Knight Ghost himself.
- In the film The Other Side of the Door: Maria sees her daughter Lucy sitting on the bed, facing away from her and crying. She approaches, asking whether Lucy is all right, but Lucy does not reply or turn around. As Maria reaches out to touch her daughter, someone murmurs, "Mommy." She turns around to see Lucy right next to her, saying, "You woke me up." Maria looks back at the bed and "Lucy" is now staring right at her, sporting a gaping-eyed and -mouthed Nightmare Face.
- The ending of Siren: Jonah, after reflecting on his harrowing adventure, celebrates the first anniversary of his wedding to Eva with a round of passionate sex before falling asleep. After waking up in the middle of the night, he heads downstairs to the fridge, and discovers, to his horror, that Eva had passed out fully clothed in the living room earlier that evening, and had never come up to bed at all.
- Shirley Jackson's The Haunting of Hill House is likely the Trope Maker: In neighboring beds, Eleanor and Theodora squeeze each other's hands tightly as sinister sounds emerge from the darkness in their room. Finally, Eleanor screams, the lights go on, and a startled Theodora sits up, asking what the matter is. She had been sleeping, and was clearly not holding Eleanor's hand.
"God God," Eleanor said, flinging herself out of bed and across the room to stand shuddering in a corner, "God God—whose hand was I holding?"
- In the Doctor Who episode "Hide", Clara tells the Doctor that she's not so scared that she needs him to hold her hand. The Doctor asks her why she mentioned that and she said it's because he is holding her hand. Then the Doctor holds up both hands revealing that, no, he isn't holding her hand.
- In LazyTown, one episode has Robbie Rotten dressing up as a ghost and scaring everyone around town. Robbie tries to scare Ziggy, however Ziggy assumes the ghost is actually Trixie and does not get scared. However Ziggy then sees Trixie and the rest of the Lazy Town kids are in fact on top of a tower. Now knowing the ghost can't be Trixie, Ziggy gets terrified of the ghost Robbie and flees.
- This happens in the very first scene of the Supernatural pilot. At night when Mary Winchester is about to check on the then-six month old Sam in his crib, she stops at the door seeing a dark figure looking over the infant believing him to be her husband John. However when she goes downstairs and sees that John Winchester is in a recliner in the living room she realizes to her horror that the figure is a threat who has broken into their home. She tries to go back and protect Sam, but instead gets killed by the intruder eventually leading to the Winchesters to seek vengeance for her murder several years later.
- Drew Daywalt
- His horror short Bedfellows is built on this trope. A woman hears the phone ring in the middle of the night. She has to lean across the lump on her husband's side of the bed to answer, only to discover it's her husband calling because he went for a jog and got locked out of the house. Cue her slowly looking back toward the lump under the covers next to her...
- He also penned the short film Mockingbird, featuring an unusual version of the trope: a man listens happily to his wife's voice singing to their new baby over the baby monitor. Just then his wife enters, revealing that she's been out shopping for some time...
- In Sword Art Online: Hollow Realizations, one event has Kirito and Philia questing in a cave, where Kirito promptly decides to put out the torch before telling Philia to back against the wall and keep quiet. Philia is under the impression that Kirito wants to make out with her and is startled when her hand is held. However when Kirito relights the torch, Philia is shocked to discover Kirito was standing on the other side of the cave, and the one holding her hand was actually a monster. Turns out Kirito was testing if the monsters were attracted to light and Philia is really pissed off at being misled.
- Fatal Frame II: When twins Mio and Mayu first enter the abandoned village, Mayu's hand emerges from Behind the Black to give Mio a reassuring shoulder squeeze. Only after Mio squeezes back does Mayu walk past her from several feet away. By the time Mio turns around, there's no one there...
- Several creepypasta and one-paragraph horror stories originating on Reddit use this:
- A man tucks his daughter into bed when she tells him there's a monster in the closet. He goes to check... and finds his daughter, telling him there's a monster in her bed...
- A girl hears her mother yelling for her downstairs. As she goes, she hears her mother saying "Don't go, I heard it too."
- ClickHole: In "Incredible! We Asked These Astronauts What It's Like To Be In Space", most of the fictional astronauts' replies are completely inane, but Barry Wilmore's quickly turns disturbing:
You never know true beauty until you see Earth from space, or true terror until you hear someone knocking on the space station door from outside. You look through the porthole and see an astronaut, but all your crew is inside and accounted for. You use the comm to ask who it is and he says he's Ramirez returning from a repair mission, but Ramirez is sitting right next to you in the command module and he's just as confused as you are. When you tell the guy this over the radio he starts banging on the door louder and harder, begging you to let him in, saying he's the real Ramirez. Meanwhile, the Ramirez inside with you is pleading to keep the airlock shut. It really puts life on Earth into perspective.
- In Family Guy episode "Business Guy", Lois and Carter devise a plan to get rid of Peter from the company, by having Carter dress up as a swamp monster who eats wealthy business men. It works and Peter signs the company over before fleeing. However, Carter then shows up wearing a Swamp Monster costume and asking Lois if they're going through with the plan. A horrified Lois then realizes the other swamp monster was not her dad but a real swamp monster! This then results in a Scooby-Doo style chase between Lois, Carter, and the swamp monster, who later gets revealed to be Hugh Laurie.
- My Little Pony: Friendship Is Magic has a very unusual example in "Castle Mane-ia". While exploring a haunted castle, Rainbow Dash feels a hoof around her and assumes it is Applejack who got scared. However Applejack is actually standing far away. Rainbow Dash and Applejack become terrified as the hoof is coming out of the wall and run away. Then on the other side of the wall, Rarity had reached her hoof through and just got scared as she felt something alive on the other side. In this case the "Fright Beside Them" turns out to be another friend having the same experience in reverse.
- Subverted in SpongeBob SquarePants: Sandy and Patrick try to lure SpongeBob out of his home, with Patrick dressed as a gorilla, pretending to attack Sandy. But during the "attack" Patrick suddenly enters the frame. As it turns out, the guy in the gorilla costume actually was Patrick, while the guy who entered the frame is a real gorilla in a Patrick costume.
- In Teenage Mutant Ninja Turtles (2012), while the turtles and Renet are in an Egyptian tomb Michelangelo feels someone poke him from behind and assumes it's Raphael playing a prank on him. Except Raph is in front of him; Mikey looks back and to his horror sees it's a dismembered mummy arm on his shell.
- In Total Drama, the episode "Hook, Line, and Screamer", which parodies many elements of the slasher genre, naturally includes this trope. Duncan has just confronted the Killer and managed to unmask him, revealing him to be none other than Chef Hatchet. All the losing campers cheer from the safe tent, before Izzy notices Gwen is in the mess hall with the Killer. Only for Duncan to ask in shock that if Chef was here with them, then who was with Gwen? All of the campers realize Gwen is currently with a real killer, and all of them rush over to the mess hall to warn her. They manage to get there just in time to warn her, allowing Gwen to see the danger and kick the killer in the face, whereupon he promptly runs off.
- In Total DramaRama episode "That's a Wrap", the kids visit a museum where Duncan repeatedly tries to scare the other kids. When they accidentally awaken a mummy, Courtney assumes the mummy is Duncan. Despite its repeated attempts to scare her, Courtney shows no fear and beats the mummy up. It isn't until the real Duncan, also dressed as a mummy, appears does Courtney realize the truth and finally panics.
- In The New Scooby-Doo Movies episode "Guess Who's Knott Coming to Dinner", Shaggy has left the old mine with the supposed ghost of Captain Moody, whom he mistook for the disguised Don Knotts. They are walking back to Moody Manor when they encounter the real Knotts, in his Homer Pipsqueak persona. While talking to Knotts, Shaggy looks to his side and realizes who his companion is.
- In the Mickey Mouse cartoon The Pointer, Mickey is hunting with Pluto, who wanders away when he's not looking. A bear goes after Mickey, but Mickey, thinking the bear is Pluto, keeps shoving it and slapping it on the nose when it gets too close. Eventually, Mickey sees Pluto standing in a field and says "Look, Pluto. It's you." Suddenly he realizes that if Pluto is there, then someone else has been behind him all along. So he slowly turns around...
- Minor example in one Pink Panther cartoon. The Inspector calls for his assistant, Judu, to run a lab analysis on a large gem, and a black-gloved arm reaches into the room and accepts it. Then Judu walks in, wearing white gloves on his much shorter arms...
- In the Gravity Falls episode "Into the Bunker", Dipper and his crush Wendy are being menaced by a shapeshifter. At the climax, Dipper comes upon Wendy's unconscious body, prompting him to panic and tearfully confesses his feelings for her. Just then, Wendy pops up, alive and unharmed, right behind him.
Dipper: Wendy? Wait, then who's...
(body on ground arises and attacks)