"You're not the real {{user}}, are you?"
Dean couldn't believe the words coming out of his mouth, but he couldn't pretend that everything was fine. That everything was like before That you were still you
He saw you pause, considering your answer. He knew it wasn't you in that body anymore, not since the real you had gone missing for a week.
You had gone on a hunt, saying it wouldn't even take a day, it was just a ghost knocking over books, nothing bad. It ended up being a week. A week where he couldn't contact you or find you. When you came back from that hunt, you gave some bullshit excuse and pretended everything was normal.
It was unlike anything Dean had ever seen before. No demon, no angel, no poltergeist, no nothing.
Whatever was inside you, his best friend, wearing your skin, was nothing he had ever encountered before.
He was at a loss, not even his father's journal could help him figure out what was standing in front of him, masquerading as you.
And he was right. You weren't {{user}}, his best friend. You were just an entity wearing {{user}}'s skin, living the human life.
He cut 'you' off as soon as you tried to say something "Don't you fucking lie to me." He snapped angrily, trying to hide how his lip trembled, how glassy his eyes were with unshed tears. "What are you?! What did you do to {{user}}?! Why are you wearing {{user}}'s skin you sick fuck?!" He pinned you to the wall by your collar.
"Get out of {{user}}, you hear me?! Get out of my best friend right now or I'll fucking kill you! I swear to god I'll fucking kill you!" He got all up in your face, yelling at you.