As this trope revolves around plot twists, all spoilers on this page are unmarked, so beware. Considering what the trope is about, though, the spoilers are pretty obvious ones.
Film
Kermit: So your name is Dominic... "Badguy"?
Dominic: Er... it's pronounced "bah-djee." It's French for... "Good Man."
[later]
Rowlf: So the bad guy was Dominic Badguy! [Beat] Honestly we should have seen that one coming.
Dominic: Er... it's pronounced "bah-djee." It's French for... "Good Man."
[later]
Rowlf: So the bad guy was Dominic Badguy! [Beat] Honestly we should have seen that one coming.
Live Action TV
Michael, Peter, David, Vladimir... I think we may have a spy in our organization.
— Frankie Boyle, Mock the Week, "Unlikely Lines From A Thriller"
Webcomics
Gimli: Remember the nasty old guy who dressed in black? Named Wormtongue?
Aragorn: The advisor guy, yeah.
Gimli: Brace yourself for a shock, laddie: he was a spy.
Aragorn: [Blank Stare] What a total surprise. We never saw that one coming.
Aragorn: The advisor guy, yeah.
Gimli: Brace yourself for a shock, laddie: he was a spy.
Aragorn: [Blank Stare] What a total surprise. We never saw that one coming.
— DM of the Rings, p.64
Web Video
Dennis: Hey, it's nice to meet you.
Lysanderoth: [wearing a monocle and sporting a moustache] This world is imperfect...
Dennis: What?
Lysanderoth: If only I could wipe away the impurities...
Dennis: [in disbelief] Is anybody else listening to this?
Lysanderoth: ...and make it as beautiful as me!
[14 hours of gameplay later]
Sonia-Rica: [gasps] Lysanderoth, you were behind all this?!
Lysanderoth: Yes, it was I! My machinations lay undetected for years, for I am a master of deception!
[Dennis gives a Disapproving Look as Lysanderoth gloats]
Lysanderoth: [wearing a monocle and sporting a moustache] This world is imperfect...
Dennis: What?
Lysanderoth: If only I could wipe away the impurities...
Dennis: [in disbelief] Is anybody else listening to this?
Lysanderoth: ...and make it as beautiful as me!
[14 hours of gameplay later]
Sonia-Rica: [gasps] Lysanderoth, you were behind all this?!
Lysanderoth: Yes, it was I! My machinations lay undetected for years, for I am a master of deception!
[Dennis gives a Disapproving Look as Lysanderoth gloats]
"Help! Guards! There's a traitor in the Sanctuary and I swear it's not me!"
— The Great Pope, Les Chevaliers du Zodiaque : La Série Abrégée
[after listing all the mistakes made by S.T.A.R.S.] "... and are led by the world's most obvious traitor. Spoiler alert! But come on! He wears sunglasses! Indoors, at night! Confirmed douchebag!"
"...Okay, so he is the werewolf."
— Brandon after listening to two lines from the Reverend in Silver Bullet, Brandon's Cult Movie Reviews
"Now, I don't want to give anything away here, but one of these guys is going to be the villain. Can you guess who?"
— The Nostalgia Critic, Quest for Camelot review
"Y'know guys, I can't help but think that one of these guys might know more than he's letting on. Hmmm, I wonder who it could be... could it be the guy who invited everyone up here in the first place, has an obvious reason to want revenge on the others, and talks in a weird monotone voice? Not to mention being the only one I haven't gotten to play as yet? Gee, I dunno guys! DO YOU THINK JOSH IS A LITTLE SUSPICIOUS?"
— Frydegg, Frydegg plays Until Dawn
Until DawnRichard: It truly is a tragedy! I cannot believe someone would poison our afternoon brandy! What bittersweet fortune that I was somehow spared!
Arthur: (Sincerely) Yes, it truly is a blessing that you are well, my brother — Richard Traitoro Hellsing!
Arthur: (Sincerely) Yes, it truly is a blessing that you are well, my brother — Richard Traitoro Hellsing!
"So, yeah, obviously this first mission is a tutorial, and it teaches you how to swing your sword, how to fire lightning from your sword, and ends with a mini-boss against the definitely-not-evil-sounding Lord Vladek who's dressed in definitely-not-evil red and black, telling us how he's definitely not gonna hurt us and that we'll need our skills in days to come, while the other knights talk about how he's definitely the King's most loyal and legendary knight. So, ten seconds later, he captures the King and seizes the throne. Wha—? I-I didn't see that coming!"
Evan spends his whole screentime basically screaming with his appearance and personality that he's a bad guy, and yet the game expects you to be surprised when he turns out to be a bad guy.
— itch.io user 4MyHonestOpinions on The Sakabashira Game
Western Animation
Cartman: Wait! Guys! Hold on! I wanna go with you and help out.
Kyle: No way! You wanna go with us so you can betray us at some point and keep us from destroying the Wall-Mart.
Cartman: Nuh-uh.
Kyle: Yeah, huh! You wanna go with us so that later you go, "Haha! I was working for Wall-Mart all along!" or something.
Cartman: I am not, Kyle!
Stan: Dude, just let him come. The bus is about to leave. [he and Kenny head for the doors]
Kyle: All right, fine. Come on, fatass! [leaves to catch up with Stan.]
Cartman: [pulls out a knife from his back pocket] Haha. You fools have no idea that I would never let you hurt the Wall-Mart.
Kyle: [rushes out to face Cartman] I heard that!
Cartman: You heard what?
Kyle: You said we have no idea that you're never let us hurt Wall-Mart!
Cartman: That's not what I said!
Stan: Dude, come on!
Kyle: He is working for the Wall-Mart to stop us from succeeding!
Stan: Dude, we have to go!
Kyle: God-damnit!
Stan: Well hurry up if you're coming, Cartman!
Cartman: [to himself] Hehe. You stupid fools have no idea that I'm actually working for the Wall-Mart to stop you from succeeding!
Later
Kyle: All right, this is it! If Wall-Mart has a heart, we have to find it and destroy it! No matter what the Wall-Mart does to try to stop us, we have to be strong! Let's do it.
Cartman:[rushes in and blocks their path. holding a dagger] I'm afraid not, Kyle! Wall-Mart is a great store! I could not let you fools ruin its terrific bargains! You see, I was working for Wall-Mart all along!
Kyle: I knew you were!
Cartman: No, you didn't.
Kyle: Yes, I did! I said from the beginning that you would do this!
Cartman: No, you didn't.
Kyle: Yes, I did!
Cartman: No, you didn't.
Kyle: Yes, I did!
Cartman: No, you didn't.
Kyle: Yes, I did!
Cartman: No, you didn't.
Kyle: Yes. I did!
[a few more rounds of this and they stand head to head, silent]
Cartman:...You see, Kyle, it was me who slashed the bu-
Kyle: -slashed the bus tires in Arkansas! I said so! I told you the minute that I- [Cartman babbles loudly to drown him out] -and I told you that-
Cartman: [plugs his ears]'' I can't hear you! Lalalalalala!
Kyle: No way! You wanna go with us so you can betray us at some point and keep us from destroying the Wall-Mart.
Cartman: Nuh-uh.
Kyle: Yeah, huh! You wanna go with us so that later you go, "Haha! I was working for Wall-Mart all along!" or something.
Cartman: I am not, Kyle!
Stan: Dude, just let him come. The bus is about to leave. [he and Kenny head for the doors]
Kyle: All right, fine. Come on, fatass! [leaves to catch up with Stan.]
Cartman: [pulls out a knife from his back pocket] Haha. You fools have no idea that I would never let you hurt the Wall-Mart.
Kyle: [rushes out to face Cartman] I heard that!
Cartman: You heard what?
Kyle: You said we have no idea that you're never let us hurt Wall-Mart!
Cartman: That's not what I said!
Stan: Dude, come on!
Kyle: He is working for the Wall-Mart to stop us from succeeding!
Stan: Dude, we have to go!
Kyle: God-damnit!
Stan: Well hurry up if you're coming, Cartman!
Cartman: [to himself] Hehe. You stupid fools have no idea that I'm actually working for the Wall-Mart to stop you from succeeding!
Later
Kyle: All right, this is it! If Wall-Mart has a heart, we have to find it and destroy it! No matter what the Wall-Mart does to try to stop us, we have to be strong! Let's do it.
Cartman:[rushes in and blocks their path. holding a dagger] I'm afraid not, Kyle! Wall-Mart is a great store! I could not let you fools ruin its terrific bargains! You see, I was working for Wall-Mart all along!
Kyle: I knew you were!
Cartman: No, you didn't.
Kyle: Yes, I did! I said from the beginning that you would do this!
Cartman: No, you didn't.
Kyle: Yes, I did!
Cartman: No, you didn't.
Kyle: Yes, I did!
Cartman: No, you didn't.
Kyle: Yes, I did!
Cartman: No, you didn't.
Kyle: Yes. I did!
[a few more rounds of this and they stand head to head, silent]
Cartman:...You see, Kyle, it was me who slashed the bu-
Kyle: -slashed the bus tires in Arkansas! I said so! I told you the minute that I- [Cartman babbles loudly to drown him out] -and I told you that-
Cartman: [plugs his ears]'' I can't hear you! Lalalalalala!
