In my third form at school when I was 13 an incomprehensible dispute fiercely divided the class. It started innocently enough. Whenever a hole appeared in the classroom's woodwork, someone would write alongside it "The phantom woodworm strikes again." It was very schoolboyish and began to be accompanied by a little picture of the worm, sideways on and made up of rounded segments and with a small hat on the top. The worm was christened "Fanty" and became a sort of class mascot.
It was all very amicable until a few class members began to draw a small beetle instead, setting it up as a rival mascot. So "Fanty, the phantom woodworm" now faced off against "Bilgie, the bilge-water beetle." The class took sides and divided between those supporting the different mascots. Insults were traded on the blackboards between lessons, and the two groups tried to outshout each other during break with the names of the rival mascots, Fanty and Bilgie.
No actual fights took place, but the rival groups began to play quite mean tricks on each other's supporters, and there were some fairly heated confrontations. It went on for many days, but before it could break out into open warfare the school's authorities ascertained what was happening and intervened to shut it down. No more drawings or slogans were permitted, under sanction of heavy-handed punishments. The two sides made a sullen and resentful peace, and a week later it was all gone and no-one could remember what all the fuss had been about.
While it had lasted, though, it was intense. Had it happened in an American inner city school, no doubt the two gangs would have been blasting away at each other in pitched battles with automatic weapons. As it was, it was a civil war in a teapot, and there were no casualties.