Brotherly Love
My brother and I are a year apart but we were always in the same school year. This confused people because they assumed we were twins and after a while were tired of correcting them. We look nothing alike. Out of boredom we devised an elaborating story that we rehearsed perfectly.
We were able to convince a handful of girls that we were identical twins. We said that the reason my brother was shorter and looked nothing like me now was because he was in a car accident when he was young.
Due to the car accident his growth was stunted and needed plastic surgery which made his face thinner and ugly. We had one girl convinced for three years. She brought it up one day and every one of our friends looked at her like she was stupid. Story credit: Reddit / Yes_it_is_that_big