Basic Trope: A good-guy character is revealed to be not good at all later on.
- Straight:
- Bob's pleasant approach toward Alice is just a ploy for one of his evil deeds.
- At first, Bob appears to be an ally for the good guys, but he's later revealed to be a henchman of the Big Bad (or the real Big Bad).
- At first, Bob appears to be a standard Hero Protagonist, but he turns out to be the Big Bad (or a Villain Protagonist).
- Exaggerated:
- Bob convinces everyone to help him in his supposed goal to bring about world peace, but it turns out his real intentions are to make everyone get into a massive war that will result in all life being wiped out.
- Bob pretends to be friendly but he's really the Devil.
- Bob seems like a paragon of goodness at first, but turns out to be nothing short of pure evil.
- Downplayed:
- Bob at first seems to be a Nice Guy, but it eventually turns out he's a Jerkass.
- Bob turns out to still have pretty strong standards.
- Bob turns out to be Obliviously Evil.
- Bob turns out to be a bad person but is actually a genuinely nice dude in spite of his dastardly decisions.
- Bob turns out to be part of a group of villains, but he is more or less the Token Good Teammate of that bunch of bad apples.
- Bob was unpleasant even before he was revealed to be evil.
- Justified:
- Bob had to pretend to be good so that the people he's manipulating wouldn't suspect anything until it was too late to stop him.
- Bob needs to understand Alice's personal problems, relationships, and motivations in order to gain an advantage over her.
- Inverted:
- Good All Along
- For some reason, the genuinely benevolent Bob starts convincing everyone that he's actually the bad guy.
- Subverted: When Alice comes to the conclusion that Bob is actually evil, she turns out to be mistaken.
- Double Subverted: Bob actually was evil and simply tricked Alice into thinking she misjudged him.
- Parodied: Bob is a Devil in Plain Sight and yet everyone he's deceived act surprised when he finally admits to being the bad guy.
- Zig Zagged: Some hints are dropped that Bob might not be as good as he seems. He gives a reasonable explanation for the signs that he might be evil, but it's not clear whether he's telling the truth or simply using lies to continue the deception that he's good.
- Averted: All good characters actually are good and are not villains pretending to be benign as their cover.
- Enforced: "We need a good twist to end this season on, so how about we reveal that one of the heroes was actually a bad guy the whole time?"
- Lampshaded: "I can't believe we were tricked into thinking that a psychotic despot was a benevolent ruler!"
- Invoked: Bob knows that the best way to get Alice to help him in his schemes is to convince her that he's on her side, so he pretends to be a good guy to manipulate her into helping him.
- Defied: Alice has a lie detector with her at all times (or is a Living Lie Detector) so she can tell whether anyone claiming to be on her side is telling the truth or simply trying to manipulate her with lies.
- Discussed: "How could you trick me like this, Bob? Villains are bad enough as they are without manipulating people by pretending to be good guys!"
- Conversed: "Man, it's getting ridiculously easy for the bad guys to trick the heroes into thinking they're on their side."
We gotta stop the person we thought was our ally now that it turns out he was Evil All Along.
