kuchisake-onna
An old Japanese legend-turned-urban legend of a woman who had her face cut up (either by her husband or by failed plastic surgery), and her ghost haunts young people.
She wears a face mask and asks people if she looks pretty.
If they answer "No" she immediately kills them with a scythe or scissors. If they answer "Yes", she takes the mask off, revealing her horribly cut face, and asks "How about now?", before killing them
In other versions of the tale she says "Wanna know how I became like this?" after taking the mask off, and cuts the face of the victim making them look like her (especially if they are young women).
There are supposedly two ways of escaping her. One is responding "You are somewhat attractive to me" or just "So so", which may confuse the ghost and give you time to escape. The other way is by repeating everything she says, which may cause her to disappear.