When I was just starting secondary school in the late 1960s, I was tall for my age (5 ft 4) and a bit overweight. All the boys in my year group were smaller and lighter, as were most of the girls. There was a particular boy in my class who was extremely small. I was an early developer and he was probably a late developer- as I was born in early December, he was probably on reflection about 9/10 months younger than me, which makes a difference at that age.
One day, during a Geography lesson in the first year, I was called to the front of the room. The teacher (a male in his forties) then invited the smallest boy in the class to join me. We were supposed to point out various countries on the map on the wall, but the boy started to play the class clown and pretended to be “frightened” of me because of the difference in size. Of course, he got all the laughs when he pretended to run away from me. All I felt was humiliation and wanted the ground to swallow me up. The teacher just stood and laughed along with everyone else. I was totally mortified.
This person continued with the teasing (bullying?) most of the First Year, but as I progressed into the the Second and Third Year, this stopped. I remained at my original height and lost the weight but he continued to remain small. By the time I reached 4th or 5th Year all the boys, except this particular boy, were taller than me and I even had a “boyfriend” in the 5th Year.
In my last year at school, I moved to a different town in the same area and started a secretarial course. I lost contact with most of my old school friends and made different friends at College. One night, with three friends from College, at the local Palais when I was 18, I came across this school bully. I noticed him looking across at us from the bar with two friends. He swaggered across to us with his friends and tried to engage me in conversation. By this time (of average height and slim with two good-looking friends) I pretended not to recognise him, but instead smiled up at one of his friends who immediately asked me to dance. The taller friend asked one of my other friends to dance, which left my small bullying former classmate with my other friend. When I looked across the dance floor after a few minutes he was gone. My friend had seen him off. Not wanting to leave my other friend on her own I made a note to return to the table after my dance but she was soon asked by someone else to dance so I need not have worried.
When we all returned to the table, I asked my friend why she had sent my ex classmate away. She said she bluntly told him that she couldn’t dance with someone under 5 ft 7 (shallow, I know, but remember we were 18 year old girls and he was 5ft 5 at the most). I remember seeing him alone at the bar looking somewhat dejected but didn’t feel guilty as I felt that karma had taken place.
I still see him from time to time (mainly at the supermarket) and I still pretend not to recognise him. I’m always polite but always very vague and once when I was with my partner and he asked who he was, I replied (in a voice the ex-bully could hear) that I really couldn’t remember him at all. I don’t really think about this person much at all, but this thread got me thinking what did to me as a 12 year old and the effect it had on me. He is still small, divorced and looking for another partner (so he told me) whilst I am happy with my partner. He was the class clown - who has had the last laugh? 
PS I feel more hatred/contempt for the teacher who allowed the teasing/bullying to take place. It wouldn’t happen today.