Any significant injury that results in paralysis would be a potential candidate. These become possible as soon as you become old enough to climb things like trees.
A kid in my class put his arm inside a... I don't remember if it was a lion or tiger cage back on the 70s before safety was a thing. Being armless isn't the end, but I bet he regretted that decision.
There went all his hopes for an army career. No more pitching for the Mets. No more professional arm wrestling. No more rowing competitions, or stirring huge pots of gruel.