Now, Surprise Creepy seems to be two related but different concepts rolled into one trope- works that have a creepy portion which clashes with the rest of the work (momentary Surprise Creepy in otherwise non-horror work), and works that are straight-up horror masquerading as another genre (the entire work is Surprise Creepy). While they have the same idea behind them, I do feel these are distinct enough concepts that they can be split into two sister tropes, with Surprise Creepy keeping the name for the momentary horror and Stealth Horror Story for the other use. There is also concern that the "entire game is Surprise Creepy" may be misuse as the description appears to lean more towards the "momentary Surprise Creepy" interpretation.

Also note that some examples will be in a main namespace like Literature or Video Game despite me getting there from one of the Moments pages, but I felt that the main page wick that elaborates on the example would better represent the example and make the difference more clear.

The wick check, to support this, found a pretty even split between both types of examples, with only the non-horror works being slightly more.

Wick check: Sandbox.Surprise Creepy Wick Check

1. Series.Taskmaster: The introduction to "A Fat Bald White Man"'s Felling Ducks task has the typical visual showcase of the task with the typical music being cut into a few times with discordant shots of the aftermath of the task, making it look like a horrific rubber duck massacre.
2. Anime.Master Of Martial Hearts: The anime seems to just be a typical Panty Fighter tournament series for the first four episodes, but there are hints that the Platonic Heart tournament is Not Just a Tournament. The final episode comes with the grisly reveal that all the losers are kidnapped and drugged to become Sex Slaves, and the losers of this tournament are shown in full detail having been drugged so thoroughly that they are laughing like crazy, completely brain dead as their handers treat them like pets, and Aya is aghast at what has been done to them (especially since one of them is her chemistry teacher), all while creepy music plays in the background.
3. Trivia.Boxxy Quest The Gathering Storm: Throw It In!:
   • An elaborate easter egg called “Easy Mode” was planned but ultimately scrapped in favor of releasing the game sooner. It would have pretended to be a lower difficulty option, before unraveling into a dark, Creepypasta-esque version of the game, and have Rcoastee, who is the Final Boss and major antagonist from the original game, return as the mastermind. Apparently, several things would have played out differently in a post-Easy Mode playthrough. Of this huge secret, only a few unused sprites and a Dummied Out cutscene remain intact.
4. VideoGame.Wadanohara: The second half of the game. The first half is pretty much interacting with cute animal people and facing down your enemies. Then Tosatsu Kingdom invade and people start dying, and Sal reveals himself as the one behind everything, though even then it's not so bad - but then you come across your familiars dying, covered in blood with missing eyes and limbs or cut in half. Of course, it's just an illusion, but the game gets worse from there on out. Reached from NightmareFuel.Wadanohara.
5. Manga.The Demon Girl Next Door: The manga is a light and fluffy tale that takes place in a world where the only real problems are comical misunderstandings, easily solved by our intrepid, peace-loving heroine. Then there's Suika, a genocidal monster Momo defeated ten years ago, that Shamiko learns about when she dream-dives into Momo's memories. On her defeat, Suika turns into a creepy shadow form made of black marker scribbles with two round, empty, profusely weeping eyes, announces she knows Shamiko has been dream-watching the whole time, and pledges to return soon and murder her. Oh, and vol. 6 has a full-color page of Shadow-Suika's face with a creepy Cheshire cat grin, surrounded by two dozen extra eyes, all staring directly at the reader. Good luck sleeping.
6. Characters.Senran Kagura Nintendo 3 DS (Orochi): Vile Villain, Saccharine Show: Prior to her and Dōgen's appearance, the story is a lighthearted Fanservice-fest with villains who are goofy and shown to be good people deep down. Then she shows up and instantly raises the stakes by being a genuinely scary Eldritch Abomination who takes the game into Surprise Creepy territory. The first game actually resembles a Kirby game in this regard (fanservice not withstanding)- 99% of it is a lighthearted romp, only for the last 1% to abruptly introduce a creepy, eldritch Final Boss.
7. HarryPotter.Tropes S To Y: In actuality, the books (and by extension, the movies) often utilize deeply unsettling imagery and deal with dark themes such as death, loss, and betrayal in a frank and uncompromising manner. Make no mistake about it, there is genuine horror in the Harry Potter series.
8. Heartwarming.Key And Peele: It's hard not to be happy for the guy in "Continental Breakfast", who marvels at a pretty-standard hotel breakfast buffet and works himself into sobbing with Tears of Joy over eating yogurt and mini-muffins. Even the twist ending of the sketch doesn't do much to put a damper on it, as the guy seems happy and chill enough with the revelation that he's a ghost who's always been at the hotel... and cruises right off to grab some more breakfast.
9. Housepets.Tropes M To Z: If it were ever possible in text form, then the little demon that befriends Keene in "Temple Crashers 2" pulls it off when agreeing to help Keene and Breel escape "the bad place." His Heel–Face Turn from hanger-on to menacing entity is unexpected, but in retrospect makes sense:
   Demon: I found Breel! He's chained!
   Keene: That's nice, but I can't do anything about it unless I had my cap...
   Demon: I can get cap for you! Just take me to Earth!
   Keene: Fine! Whatever! Just be quiet about—
   Demon: THEN THE CONTRACT IS SEALED
   Keene: (widens eyes)
10. NightmareFuel.Gravity Rush 2: After defeating Kali Angel and Durga Angel (Cecie), the latter comes to their senses, causing the former to have a Villainous Breakdown and suddenly morph into a massive, blobby monstrosity with multiple screaming faces of different sizes (that all still resemble the original person) and multiple arms and legs with grotesque swollen growths. Its weak points are its eyes, which explode bloodily after a few hits. Also counts as Surprise Creepy, given the lack of gruesome imagery or gore up to this point.
11. NightmareFuel.Playstation All Stars Battle Royale: During Fat Princess's ending, her kingdom is elated to see their princess return, but are a little disappointed that she hadn't brought back any cake with her. The narrator then tells us that the princess did bring something along with her to help her rule her land, and when he says this, the princess suddenly looks at the camera with a rather unsettling smile on her face, while glowing with the power. It's a bit unnerving for a character so goofy.
12. NightmareFuel.Queen: The intro to "Death On Two Legs" is really unsettling. Starting with a fade-in on a rapid piano pattern, then adding a repeated four-note guitar riff isn't too bad. No, it's doubling the guitar with a growling double bass, layering in overlapping high-pitched glissandi, and finally somebody screaming, growing louder and louder...and it abruptly goes silent, replaced by the melody and chords in the piano. Did we mention this is beginning of the entire album?
13. NothingIsScarier.Video Games: Psychonauts: Although a quirky and humorous platformer for the most part...Milla's Dance Party surprisingly also has a example of this. While most of the Mental World is colourful, fun and groovy if you levitate over to an easily missable opening you find a conversely dark and creepy room, sparsely filled with children’s toys and a mental vault revealing Milla used to run an orphanage that accidentally burned down.
14. Recap.Adventure Time S 1 E 5 The Enchiridion: Kick The Son Of A Bitch: Finn saves 3 flying gnomes from a lava pit, only for them to kill several old ladies. Jake responds by rounding them up and throwing them right back into the lava pit.
15. Recap.The Simpsons S 4 E 14 Brother From The Same Planet: Bart's Imagine Spot where Homer partially melts and the landscape turns hellish is very grotesque and horrific, comes out of nowhere, and is really out-of-place in a normal Simpsons episode (and would arguably be too much for even a "Treehouse of Horror" episode).
16. Sorting Algorithm of Threatening Geography: Pokémon Red and Blue and the remakes have the aforementioned settings as Route 1 and Viridian Forest, respectively. Then, in between the occasional road and field, the player encounters Mt. Moon (a cave), Rock Tunnel (a cave and a Blackout Basement), Pokemon Tower (starting a proud tradition of putting uncharacteristically scary areas in cute monster collection games to give kids nightmares), Rocket's Hideout (incidentally, every game also features at least one criminal hideout, which often overlaps with Container Maze and/or Eternal Engine), Seafoam Islands (a cave in the sea that combines Slippy-Slidey Ice World with treacherous currents that drag you around), and Pokemon Mansion (the derelict ruins of a house that used to double as a lab where some, er, less than ethical experiments were conducted.)
17. VideoGame.Vine Worlds: After the VSS Tums, a lighthearted, largely Star Trek-inspired area comes The Anomaly, a reality warping borg-like temple in a cosmic pocket dimension full of eldritch-looking chatyots, almost all of which speak in ominous prose.
18. YMMV.Bobs Burgers: Crosses the Line Twice: In "Dream a Little Bob of Bob", Mr. Fischoeder's version of the hand-slapping routine is fairly tame. That is, until it gets to a line revolving a disastrous fire in which numerous people died. Mr. Fischoeder's dissonant cheerfulness makes it even funnier.

    Fischoeder: How many people died in the fire?

19. YMMV.Felix The Cat: Nightmare Fuel: The Game Over screen in the Sega Genesis bootleg version is a particularly brutal example of Surprise Creepy. When you lose all of your lives, you are taken to a continue screen featuring Felix in a Fluffy Cloud Heaven, exactly the sort of thing you would expect from a game like this. Except, when you click "no" (or rather its Russian equivalent), you are treated to a shot of Felix having torn his face off and standing in a pool of his own blood. The reaction that Joel from Vinesauce had to it sums it up.
    "WHAT THE FUCK IS THAT?!"
20. Terraria.Tropes S To Z: The player's first night, most likely. Sure, it's a cheerful sandbox game that takes place in a cutesy Sugar Bowl world, but then night falls and the zombies and flying disembodied eyeballs show up...
21. NightmareFuel.Super Mario 64: The Mad Piano in Big Boo's Haunt. It's pictured on this page for a reason; much Mario-related trauma has come from that enemy alone.
    • Let's set the context: after having explored lighthearted worlds (even Jolly Roger Bay has comforting music to settle down the loneliness), you discover a Boo in a corridor. It leads you to the backyard where all its friends are waiting for you and when you find it, it holds a kind of birdcage. After managing to defeat it, the cage falls on the ground and sucks Mario. After the Star Select screen, you are now in Big Boo's Haunt, a dark level with a howling wind, disconcerting music, and big bars around it, giving you the feeling you're stuck in a birdcage. The area's boss kindly invites you to come in.
      Big Boo: Come on in here... heh, heh, heh...
22. YMMV.Yoshis Crafted World: Nightmare Fuel: "Be Afraid of the Dark" is a terrifying level in a cutesy, charming game. The level's primary enemies are invincible slasher-like Monster Clown ragdolls with axes chasing you throughout the stage. They can pop out from the background at any moment, make a horrific screeching sound when doing so, and one moment has them appear en masse when you hit a winged cloud. Even worse is the atmosphere, since almost everything is dark and dreary, and even the text boxes are ominous jumbled phrases that would feel more at home in a psychological horror game. And to top it all off, there's red paint on the walls as a stand-in for blood.
23. Literature.Villains Are Destined To Die: Imagine playing the easy mode game as sweet, lovely Ivonne and then paying to see the hidden route and finding out that "Ivonne" was the true villain who succeeded in killing the true protagonist and destroyed the world. Seems to be an In-Universe example as well as out-of-universe.

1. Characters.Nifty (The Antagonist): Vile Villain, Saccharine Show: The game starts off a cutesy puzzle game, and may have intended to be that by Garalina, but once the AI appears after Level 10 and starts Addressing the Player, that is when the meta-horror begins. It later proceeds to kill Nif and is revealed to have driven prior players to suicide. Spoiling the example for those who want to play it for themselves.
2. ComicBook.Beautiful Darkness: In the first couple pages, Aurora is enjoying a tea party in a round pink room, only to step outside through the eye socket. After that it quickly stops being a surprise.
3. Film.Munchausen 2013: What starts off as a Pixar-esque sequence (much like the first ten minutes of Up's opening or the ending of Toy Story 3), ends with the son dying because of the mother's reckless actions.
4. Literature.The Fifth Step: The story is uncharacteristically low-key for King. Right up until the ending, when we find out that we've been listening to the life story of a ruthless murderer, and that our protagonist is his next victim.
5. Recap.Kaeloo S 1 E 7 Lets Play Trap Trap: The episode starts off with a seemingly normal plot where Kaeloo, Stumpy, Quack Quack and Mr. Cat play a nice game of Trap-Trap, with the beginning being so sweet that Kaeloo even gives Mr. Cat a hug. Then, halfway through the episode, Quack Quack goes insane, tries to cannibalize Kaeloo and Stumpy, and successfully eats half of Kaeloo's brain, leaving her unintelligible. Mr. Cat has to step in and save the day.
6. SoundtrackDissonance.Video Games: Doki Doki Literature Club! starts out as a lighthearted Romance Game, or Affectionate Parody of one, with a soundtrack to match. After the Surprise Creepy Genre Shift sets in, it still mostly uses the same soundtrack.
7. VideoGame.Clicking Bad: Defied; unlike Cookie Clicker, the evil is upfront-and of a less supernatural bent. refers to this interpetation of the trope
8. VideoGame.Needy Streamer Overload: Do not let its upbeat theme song "Internet Overdose" and its colorful and cheery graphics fool you — this game is actually a realistic portrayal of a mentally ill girl struggling in self-management and the bitter side of internet culture. Some of the possible endings are also rather depressing.
9. VisualNovel.Doki Doki Literature Club: The game is initially presented as a cute Romance Game where you romance the girls using poems they would like, but things get a little darker when serious subjects like depression and suicide come up. Then, when you replay the game after Sayori's suicide, things start to get even more disturbing, like obvious glitching, Yuri's Sanity Slippage, and Monika's true nature. Reached from TearJerker.Doki Doki Literature Club.
10. WebVideo.Dont Hug Me Im Scared: The entirety of the DHMIS series is mostly on trope. Reached from YMMV.
    • The first "Don't Hug Me I'm Scared" starts out innocently enough, with a talking sketchbook encouraging Sesame Street-style puppets to get creative to a catchy song. By the end... well, let's just say that they take it a bit too far.
    "Now let's all agree to never be creative again!"
    • The second video starts normal enough, the puppets are waiting to watch their favourite show, Tony shows up and things start out like the usually would in a kids show, this time about... well, time. Cue the main puppets rapidly aging to death near the end of the video.
    • The group in the third video go from happy-go-lucky friends trying to show Yellow Guy platonic love to a cult that's trying to get Yellow Guy to join so he can find his feminine "special one". They also feed a giant stone monster they call their king and wear suits with mineral-made hearts and golden rings.
    • Colin in the fourth video. When Red Guy gets angry at Colin and slams his hand down on the keyboard, Colin shrieks and the puppets are glitched into an acid trip-like segment where everything is flashing and glitching all over the place. Things are back to normal for a while, but that doesn't last for long.
    • There was an interview with the cast-members, in-character, and for the most part they gave off amusing or non-sequitur responses, until the last question, in which they ask Roy what his thoughts are.
      "My silly boy has allowed his eyes to grow arrogant and rude, for this I will take him on a trip to punish land."
    • 5 also does this to a lesser extent, it start of with a "song" on health (well, the bands nonsensical version of it, anyway), but the creepiness comes in much earlier and keeps building on it.
    • 6 Averts this, it's creepy and strange all the way through.
11. VideoGame.Fancy Island: The home page of the site makes it look like a typical, cutsey anime game, with a Moe Cat Girl going through the titular island and an also-cute cat spirit explaining the rules. But once you click on the image leading to the rest of the site, you are immediately greeted with what looks like the entrance door to a haunted house, and entering greets you with the unnerving head of what appears to be a Stringy-Haired Ghost Girl (or, sometimes, a Creepy Doll head which cries blood and creepily laughs if you click on it). And it all goes downhill from there, with Nightmare Face after Nightmare Face and plenty of Surreal Horror.
12. VideoGame.Bonnies Bakery: The trailer and first half of the game play it up as another cutesy cooking game starring a cute girl chef in a World of Funny Animals in her quest to serve them delicious food and make them happy. Then the second half reveals Bonnie is a Serial Killer who has been kidnapping the animals and turning them into her meat, and you switch control to a hostage trying to escape her blood-and-skull-filled basement.
13. VideoGame.Bubbaruka: The game, on the surface, is a Tamagotchi-style pet raising simulator where you pet, feed, and play with adorable creatures. For your first pet, you can play a skiing minigame where you collect coins in a snow world. If you collect 10, a side path opens to a cabin… which turns out to be a dark building where your pet's eerie footsteps can be heard. The game glitches and you are promptly booted out, but you can go back in to the house, which is actually a Haunted House. From then on, the game becomes an Explorer Horror where you navigate various haunted areas, avoid the spirits haunting the game, and slowly piece together the mysterious disappearances of the game's developers through notes they left.
14. BestKnownForTheFanservice.Video Games: Inverted with various pornographic Qix knockoffs, where they're remembered more for their blatant copyright infringement and the women turning into abominations such as Pinhead than the actual erotic content.
15. VideoGame.Sofia: Lampshaded by the creator, who admits that the game was made on the concept of "cute exterior hiding dark horror interior". It starts out innocently enough, with Crow going to meet his cute boyfriend and them having a fun day together. Then a masked intruder breaks into the house at night and it turns into a horror game. Later on, the seemingly happy Jenkins household is revealed to have been one giant, horrific experiment in immortality through cloning.
16. WebVideo.Alantutorial: The series begins with a bumbling, tutorial-obsessed man making tutorials and asking for likes and subscriptions in what seems to be a parody of typical YouTube tutorials. Things go downhill when Alan is locked out of his room, creating tutorials that make even less sense than before, and seems to live in recluse in the woods before being kidnapped and stuck into a small white room by an unknown person or people. Alan's room gets progressively filthier and freakier (and he creates a man out of dollars to keep him company) until he is apparently abandoned, the lights go out, and he breaks out of the white room by smashing through a wall with the money man in tow.
17. VisualNovel.Dont Toy With Me: On the surface, it is a cute story about two adorable Living Toys learning to befriend each other in spite of their differences. Then the owner starts playing favorites and antagonizing the other toy, and it eventually leads to one of them snapping and murdering the other, with one of the routes revealing that the owner has previously killed other toys for not getting along with Dahlia.
18. Manga.I Want To Hold Aono Kun So Badly I Could Die: As the description states, the series starts off mostly innocently enough, seemingly being some Slice of Life romance about Yuri and Aono's ghost. That is, until Aono suddenly demands that Yuri allow him to possess her near the end of the first chapter, revealing the horror aspects of the manga.
19. VideoGame.Prom Dreams: Content warning at the beginning of the game notwithstanding, the game begins as a fairly typical harem dating sim, complete with upbeat music, comedic scenes, and many of the genre's standard tropes. In fact, the player can win their chosen love interest's heart and make it to prom night without experiencing a single horrific element, only for said love interest to be killed suddenly and brutally, without any way for the player to avoid it. From there, the game "resets" itself several times, sans the girl killed in each previous loop, with the atmosphere becoming more horrific as the dating sim plot gives way to a supernatural murder mystery.

1. Manga.Pokemon Adventures: The artwork, especially Mato's, is rather cutesy, the plot usually starts out lighthearted, it's Pokémon for god's sake, so it's a bit of an eye-popper when some of the more violent actions come up.
   • Pokémon indeed... Speaking as someone who has read the manga, this is Type II.
2. Laconic.Turnip Boy Commits Tax Evasion: A sentient turnip is sent on fetch quests as punishment for not paying his taxes. Things escalate from there. sinkhole
3. Literature.The Candy Shop War: Look at that kid-friendly, carefree cover. Now highlight the spoilers.
4. EarthBound.Tropes N To S: Most of the game is a gloriously strange and funny romp through childhood, and then you enter Giygas's lair. Type II, even though Gigyas is far from the only moment of Surprise Creepy in the game, just the most memorable.
5. WebVideo.Khonjin House: Nearly every episode featuring Pent.
6. Meat-O-Vision: In the Little Audrey short "Butterscotch and Soda", when her nanny tries to curb Audrey's Sweet Tooth, she looks around her room for any candy she has stored away and hallucinates an umbrella as a candy cane and her canary as chocolate. Things get darker from there.
7. Ecco the Dolphin: You wouldn't think a series about a dolphin could possibly be this eerie, would you? Is Type I, but the example does not make that clear.
8. VisualNovel.Higurashi When They Cry: The arcs are generally fun and games at the start before paranoia and murder set in. Is Type II, but the example does not make that clear.