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.
2002
2019
1993
2013
2008
2010
2022
1965
2006
1970
2024
1939
2018
1937
2021
2023