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.
2023
1929
1931
1928
1994
1989
1934
1955
1956
1951
1950
1947
2018
1942
1944