Eyes Are Mental

"Giles: How did you know it was me? Buffy: Your eyes. You're the only person in the world that can look that annoyed with me."

- Buffy the Vampire Slayer, "A New Man"

Alice and Charlie are grieving over the loss of their friend Bob. Bob has been separated from the group, perhaps he has been killed or kidnapped by the enemy. One of two things will happen.


 * 1) They are then confronted by a monster, who chases after them. After being cornered, the monster either speaks or does something to demonstrate that he is, in fact, Bob. The others refuse to believe him, until one or the other gets a look at Bob's eyes, and recognize his eyes.
 * 2) Bob will miraculously return, seemingly unharmed. After getting over the initial shock, Alice and Charlie rejoice at having Bob back. After a while, however, something seems to be wrong with Bob. He's acting strange and might have something off in his voice. Then, Alice gets a good look at Bob's eyes to find the eyes of a monster. Alice and Charlie then realise that their Shape Shifter enemy has taken Bob's place, in an attempt to gain their trust.

It seems that by some law of Shapeshifter Baggage, Shape Shifters are unable to change their eyes, no matter how skilled they are at changing form. See Glamour Failure for a similar trope and Voices Are Mental for the vocal version of this trope.

A specific type of Morphic Resonance.

Type 1
"Johnny: "Your eyes never changed, you know." Ben: "Huh?" Johnny: "Your eyes never changed. I mean, yeah, the rest of you is a freak, but your eyes are still the same." Ben: "You noticed my eyes?" Johnny: "I notice stuff. I'm not smart like Reed or Sue, but I notice stuff." Which is why Ben is "the ever-lovin' blue-eyed Thing.""
 * Kingdom Hearts II: Riku has taken the form of the last game's Big Bad to fight The Heartless. When Sora is reunited with Riku, he only believes it's him when he sees, well, Riku's heart. But after he realizes who it is, Riku's eyes, and voice, change back to normal.
 * Beauty and the Beast: Inverted Trope, Belle is not fully convinced that the transformed prince is in fact the Beast, until she takes a good look at his eyes.
 * In Ultimate Fantastic Four, Johnny Storm cheers up Ben Grimm by commenting that his eyes never changed. The dialogue went something like this:


 * In Last Res0rt, Alice Quinn cannot change her dead eyes.
 * Scanners. The ending.
 * Interesting Times: "Gods can take any form, but the one aspect of themselves they cannot change is their eyes, which show their nature." The Lady and Fate are mentioned as specific examples.
 * In the same vein, Teatime's eyes in Resurrection Men are a fanfic example.
 * This applies to everyone in the Discworld universe. Nothing magical can change the appearance of a creature's eyes, even though you can potentially change every other part of their body.
 * A non-monster example in Heaven Can Wait (1978). At the end of the movie, when Betty looks into Jarrett's eyes she recognizes that he's actually Joe in Jarrett's body.
 * The master in Krabat has magic to take on a different appearance, but he'll always be missing the one eye he lacks in real life. Also applies to animals he creates. (When Krabat tries to run away, he repeatedly meets black animals with one eye - it's not sure whether they're the shapeshifted master, or created by him.)
 * This is Older Than Feudalism. Slavic oral tradition dictates that werewolves have human-y eyes while in wolf form.
 * Rave Master used this straight. When they were in the Demon Lord's aircraft, they split from Musica, who was believed to have died by everyone but Haru. They then encountered a werewolf who was then turned back to Musica, by a magical Elixir.

Type 2

 * Mystique from the X-Men movies: For the most part averted, but her reptilian-like eyes will occasionally flash while in another form.
 * A one-off villain from Darkwing Duck, called the Chameleon, could turn into practically anything, but her eyes remained unchanged. Oddly enough, the characters never mention this and are only able to tell who she is by the hiss in her voice.
 * In Around the World with Willy Fog, Master of Disguise Transfer looks and sounds exactly like whoever he's impersonating, but he has a characteristic evil glint in his eye to tip the viewer off. (As in the Darkwing Duck example, the characters never notice this.)
 * In King's Quest VI, the genie is a shapeshifter who always has golden glinting eyes, even in nonhuman form. Noticing this allows you to avoid getting tricked or killed by him.
 * In Tim Burton's Alice in Wonderland it's not revealed to the audience that the Cheshire cat has  until he looks up and we see his cat eyes.
 * In Code Lyoko, when XANA possesses someone, the only visual clue is their eyes flickering and switching between normal and XANA's eye-like symbol. The same goes for polymorphic clones as well.
 * You can tell when someone is possessed in Yumekui Merry by their eyes. Or the audience can. It's never made clear if the characters can tell.
 * Inverted in the Animorphs #6 The Capture