It is called the Time Traveler's Paradox. In which a scientist creates a Time Machine and kills their younger self. So now a man who should not- can not- exist, somehow does. That is the Paradox, and Paradoxes are impossible.
1928
1931
2010
1993
2014
2009
2018
2008
2001
2013
2019
2022
2016
2011
—
2024
