In what seemed to be little more than high spirits, a girl at Gilmartin Elementary School in Connecticut started to throw food at a lunchtime supervisor, who responded in kind.
But when the 13-year-old punched the supervisor, Rosa Robles, the contretemps turned into a full-blown brawl.
Both the girl and the 55-year-old supervisor suffered cut lips, while the pupil also had scratches on her face. Ms Robles, who is now on paid leave, posted $500 bail after being charged with assault. The girl has been suspended, but police have not disclosed whether she will face charges.
Next time you get the urge to throw a flapjack at the pupil who is interrupting your lunch, think again.