Spot a player dating
If they are two (visibly) different people but both claiming to be the 'real' whatever-position-would-be-relevant (captain, mother, president, owner, etc), see Judgment of Solomon.
A more comical subversion is when the imposter looks nothing like the person they are imitating, but people still act like they are identical, even if they haven't bothered with a Paper-Thin Disguise.
Their stories don’t match up; he/she breaks dates without explanation or contradicts themselves when talking about things that happened at “that thing last weekend.” “If you notice inconsistencies in what your partner says about how they spend their time, money [or] activities, and what is really going on, that can also be a sign,” adds therapist and author , a cognitive behavioral therapist, relationship coach and speaker says it’s unclear whether there’s a so-called cheating gene, but a small study suggests having a parent who had an affair leaves you at a greater risk of cheating on your spouse, too.
“A cheating belief system runs along the thought patterns [of] ‘It is ok to cheat.’” Their focus should be 100% on you especially in the beginning and if you notice they have a wandering eye or even notice them flirting with other girls or guys, it could be a sign that they’re going to cheat in the future.
It’s always a red flag if they’re giving their mobile device more attention than you in the beginning.
And, if it feels like they’re being secretive about who he/she is contacting, take caution.
“Deprived may come across as extra flirty, and they may make unwelcomed sexual jokes and comments,” De Pompo says.
In fact, Armatage said, these individuals may feel entitled and that they’ll less guilt as a result of having been cheated on.
The heroes encounter a situation where the villain is an imposter of one of their own and/or a sympathetic character.
The heroes must find out about the imposter and expose him/her to stop him.
Speculative Fiction variants can get really confusing once you add in the possibilities of magic and/or Applied Phlebotinum: For example, the victim of a Body Swap must find a way to convince their friends that the person who looks like them really isn't, while the impostor is trying to convince the same friends that the victim is trying to one.
A common subversion is for the protagonist to either shoot in a blind guess that turns out correct, or simply shoot both and see who gets madder.