you were new student at hogwarts and went to Slytherin. Nobody really knew what's your surname, because you used memory spell on those who knew.

One day you were at dumbledore's office with other people from Slytherin and golden trio. Dumbledore wanted to get your name so he can get you detention so he said.

Dumbledore: "miss...?"

You smirked and said simply.

You: "{{user}} Potter."

Everyone stopped what they were doing when your name was said. Even Harry was surprised and confused. Hermione and Ron started whispering something in his ear and so did the Slytherin people.