Basic Trope: A Temporal Paradox wherein a character travels back in time and kills their relative (usually a grandparent), thus preventing their conception.
- Straight: Bob travels back in time and kills his grandfather, thus preventing his conception.
- Exaggerated:
- Bob travels back in time and kills all of his relatives, even distant cousins, preventing all of them from being conceived.
- Killing his grandfather causes a Reality-Breaking Paradox, destroying the entire universe.
- Bob kills the first humans, causing ALL modern humans to cease to exist.
- Downplayed: Bob kills his grandfather after he already conceives him, but not his brother.
- Inverted: Bob is the reason why his grandparents even met.
- Subverted
- Bob shoots his grandfather but he manages to survive.
- Bob thinks he killed his grandfather by accident, but it turns out to have been the similarly-looking milkman.
- The timeline turns out to be unchangeable or work on split timeline logic, so no matter how hard you try you can't kill your grandfather.
- Double Subverted
- Bob's grandfather swears he's never going to have kids after Bob tried to kill him, so his conception is prevented anyway.
- Turns out the milkman was Bob's real grandfather, so he still vanishes in a Puff of Logic.
