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.
1945
1951
1946
1941
2014
1940
2010
1992
1989
1993
2017
1964
2021
2022
2009
1931
2013
2024
2023