This story is a sequel to Rip
Starlight succeeds in killing the only pony who could be able to unite the six Ponies and thus permanently strip Twilight of her Cutie Mark... Shame she didn't read the fine print on time travel and realize the old Grandfather Paradox.
This is a sort of parallel story to both Rip and A Second Chance, earlier fanfics I did visiting this scenario, but instead of doing a Days of Future Past style "Time Burp" or just negating the thing altogether, I'm instead going for a Back to the Future style "Time Paradox".
Trigger Warnings: Foal death, People succumbing to the Time Paradox