A perfect example can be found in the end credits scenes of Deadpool 2, where the titular antihero is shown going back in time to stop the event that started the entire story.
SPOILER WARNING: The following article contains major spoilers for Deadpool 2.
If you have not yet seen the film, please bookmark this page, and save the read until after your screening!
To quote Dean Pelton from the television show Community, time travel is really hard to write about.