A time loop occurs in 3.11 Mystery Spot. It is a phenomenom where certain events in time keep repeating over and over again, non-stop. In this case, Sam Winchester was trapped in a loop in which his brother, Dean, kept on dying in so many different ways. As it turns out, it was the Trickster that was manipulating time and killing Dean just to teach Sam that his drive to save Dean would not end well. The Trickster eventually ends the loop, returning Dean and Sam to the current time.
- Time loops in TV shows on TV Tropes.