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.
Samuel Dunning
Tim Travers
An Affair to Remember!
A Trip to the Moon
Supermarket Sweep
The Stand
La Jetée
Another Affair to Remember!
It's a Rumic World: 50th Anniversary Weekly★Shonen Sunday
Forky Asks a Question: What Is a Pet?
Dark Star
Our Times
Beyond the Infinite Two Minutes
Il migliore dei mondi
Cycle of Time
The Conquest of the Pole
Blinky™
Primrose
Forky Asks a Question: What Is Money?
Happy Accidents
Mega Time Squad
The Heart of the World