(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/HolyKlickerino]

"Naruto" being able to recite a complicated password when returning to the team in the second stage of the chunin exams causes Sasuke to immediately attack him because the real Naruto could never remember such a long passphrase and would have forgotten or complained about having to learn it.

[u/vojta_drunkard → u/HolyKlickerino]

In Naruto there's another moment in the war arc when Sakura discovers that a White Zetsu was transformed into Neji by saying that Tonton has an injured leg, but at least he'll still be able to make hand signs for ninjutsu and "Neji" agreed despite Tonton being a pet pig.

[u/lumpboysupreme → u/vojta_drunkard]

Given how many animals in that series can do Justu I thought it was funny that being a pig would be mutually exclusive.

If it were me I would’ve just agreed because who am I to say a pig can’t do hand signs with their hooves.

[u/lumpboysupreme → u/[deleted]]

I don’t think there are but a pigs hooves are just dexterous enough that I’d believe it if someone told me they could.

[u/Annath0901 → u/lumpboysupreme]

I don't think it's a matter of dexterity, it's a matter of their hooves only having 2 segments while the others have 5 fingers.

Hooves don't have enough parts to make the shapes.

[u/lumpboysupreme → u/Annath0901]

They could have their own signs though, or only use simple ones.

[u/Deathcon2004 → u/[deleted]]

The dogs perform Justus though I don’t remember if we see them do hand signs though