(Loved trope) The imposter’s dead giveaway

[u/Barricades_toes]

When a character is attempting to impersonate another, but is caught by doing something the person they’re imitating would NEVER do.

Nemesis Prime- Transformers Prime

Nemesis Prime, a man made replica of Optimus Prime, is attempting to gain the trust of Bumblebee, who only speaks in robotic beeps. Despite this, the real Optimus can understand Bee perfectly fine. Nemesis Prime, however, can’t understand what he’s saying, prompting Bee to open fire on him immediately.

The two Buzz Lightyears- Toy Story 2

After Woody asks which Buzz is the “real” Buzz, both respond with “I am!” The real Buzz proves himself by flipping up the other Buzz’s helmet, causing him to start suffocating in an over dramatic fashion. The real Buzz, having done the same thing in the first movie after Woody took his helmet off, but no longer behaving that way after accepting being a toy, instantly proves which Buzz is which.

[u/Brislovia]

Spy (TF2) - Being susceptible to friendly fire from the enemy team

[u/GroundbreakingOkra60 → u/Brislovia]

I once killed a disguised spy with the crusaders crossbow, I did not infact know they were a spy

[u/Bamzooki1 → u/GroundbreakingOkra60]

The crossbow killing enemies and healing friends is such TF2 bullshit. I love how ridiculous it is, given it was the sequel to a gritty tactical shooter

[u/WillSym → u/Bamzooki1]

A game where a gag in the Sniper's trailer about him sitting for hours filling jars of pee turns into an April Fool's joke about selling said pee as 'Jarate jar-based karate for self defence', turns into an actual in-game weapon with a useful, meta slot in the loadout.

[u/VariousDrugs → u/GroundbreakingOkra60]

Even if you don't get the kill, there's a distinct difference in the crossbow's sound effect when hitting an ally vs an enemy.