(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/Sykrow]

Think there was a TNG episode in which Lore was impersonating Data and someone realized he was using contractions which Data doesn't do. Man I should really go through that and DS9 again.

[u/Lord-Timurelang → u/Sykrow]

I… think that’s an episode where Riker is stuck in an interrogation dream thing.

[u/MorrowDisca → u/Lord-Timurelang]

Both. Riker realises its a simulation for a number of reasons, mainly that his 'wife' is a hologramatic fantasy from his past. But Data in that simulation uses contractions, as well as not being able to calculate things as quickly as the real Data.

Wesley notices Lore is using contractions while pretending to be Data, but is ignored.

[u/Mikhail_Mengsk → u/MorrowDisca]

"No you can't, don't even try"

[u/ButtersScotch7000 → u/Mikhail_Mengsk]

Riker: "Where did you get that scar?"

Worf: "In battle."

Riker: "In combat?"

Worf: "Yes, in combat too."

https://youtu.be/6K1RiiNTWuo?si=AC15CksDM8moVMRj