Simply put, a Stable Time Loop where one is his own ancestor. Of course, this implies an Identical Grandson, and an Ontological Paradox which results in a quarter of one's DNA being created from out of nowhere. It should be noted that the song which named this trope, I'm My Own Grandpa, is not an example of the trope, as it includes no actual time travel. It describes the singer's rather complicated family life. See also Grandfather Paradox. Examples of My Own Grampa include: