South of the Border
I had heart surgery as a baby, so scar going down my chest, I also lived in Mexico eight years ago, 7th grade. When I was in high school and someone saw my scar and asked if I had heart surgery I would always respond with I got stabbed in Mexico.
Eventually I formed a whole back story to go with it, evolving location, time, what I was doing, my hospital visit, etc. Other classmates of mine would back me up at times, 1 out of 3 underclass men would believe this on average. Story credit: Reddit / callmederp