When I was young, a very tall girl used to pick on me on the bus on the way to school. One day the bus stopped at our stop on the way home (it was a centralized group stop) and we all stood up in line to get off the bus, I lit her hair on fire with my lighter.
It burned fast about 5 inches then hit the rubberband and stopped. There was a small crackle and a small wisp of smoke. She didn't know. I'm sure she realized when she got home but couldn't know who did it.
This was a long time ago so it's not really a "kids these days" thing.