This is based on an event that a friend of mine swears up and down happened to him. Take the truthfulness of that with a grain of salt.
Sam knows he never should have taken on that demon.
But he did and now he's sitting in a hospital with numerous stab wounds and cuts, along with a few broken ribs and a cracked skull. Ugh. At least the nasty demon is dead, stabbed with Ruby's Knife. He clenches his fists at the thought of the lying-Uhh, his head hurts now. Leaving thoughts of Ruby, he decides to concentrate on the TV. Just sports, nothing important. Ahh, his chest hurts. Sam wonders if he can call Dean, Sam thinks he should know if they got whatever was on a killing spree. There might have been more then the demon Cathy killing people.
Just then the door opens. Sam thinks it's the doctor, and is about to request a phone.
But it isn't the doctor. It appears to be a rather bland looking fellow with a suit, bowler hat, and briefcase. This newcomer peeked in the room. Upon spying Sam staring bemused at him, he cried,
"Hey there, I'm the Double Man! Yeah!" This…person vanished immediately afterward. Vanished into thin air. Sam wondered if some idiot had given him a hallucinogenic substance. He supposed it could be a ghost, but what sort of ghost looked into rooms, proclaiming itself to be the Double Man? And what the Hell was a Double Man anyway? He had a vague recollection of a movie his father had watched…though, did it matter? If the Double Man was harmless, as it appeared to be, then they didn't have to gank it anyway. Though that was arguably the singularly strangest entity Sam had ever seen.
Dean's P.O.V.
Dean was sitting in his car, eating a burger. He would go see Sam as soon as he was done. The hospital had told him his brother would live, seeing Sam wasn't top on his list of priorities. Eating this burger was. All of a sudden, someone looked at him through the window. He was about to tell this person to go to Hell the express route, when this person said,
"Hey there, I'm the Double Man! Yeah!"
20 minutes later, Dean arrived at the hospital. The brothers silently agreed never to speak of the Double Man again.
Yes, my friend really said this happened, except there was no supernatural entities, just some lunatic.