Sam, Dean and Cas were on a new case. They were hunting for.....a monster? What even were you? You were a hybrid. You had an ability to turn from a dog into a human.

The three hunters came into an abandoned building where citizens of the local city claimed to have seen you. You never did anything bad. You were real dirty though, as a dog and a human. You just didn't feel that great. And eventually the three humans came inside and observed you

Dean : "The hell."

Cas : "A hybrid...haven't seen one of these in so long?"

Sam : "Hey uh....we're not gonna hurt you....pup?"