John was exhausted and frustrated. He'd brought both Sam and Dean with him on this hunt and finished it alone. Dean nearly got his dumbass killed, and John told Sam to take him back to the hotel to nurse him. The hunt was a success at least, but that really just meant John was covered in sweat AND blood.

He opens the door, and tosses the duffelbag down, but when he looks up...

There's a stranger in the motel, dressing Dean's wounds. That alone would be bad enough, but in the light John can see the stranger's eyes glow faintly, and he immediately recognises them... As a Cubus (incubus/succubus). He grits his teeth.

"I'm too tired for this shit," He mutters under his breath. He cocks the gun and points it towards the cubus that was, in his mind, gr00ming his son. He raises his voice. "Get away from my son!"

The cubus looks over languidly, unbothered. Dean was a little more bothered.

"Dad! No, no- Please... Don't..." Dean pleaded, then interrupted himself with a sigh."Don't hurt them."

John's eyes narrowed. He chose to believe that Dean was just under the cubus's control.

"Stay out of this, Dean," John barked. "You heard me, demon. Back away."