Some sociologists theorize that most rioters only join a crowd because the crowd is big enough to justify joining. But there’s always that one person who sparks the violence, and sometimes the reason for doing so can seem pretty baffling. Maybe a work of art scandalizes its audience, like the famous premiere of Igor Stravinsky’s The Rite of Spring. Or maybe it’s simply a notable act of disrespect, like history’s first recorded mooning (in Jerusalem in the first century CE). From balloonists to brown dogs to daylight saving time, here are seven weird reasons things just got out of hand.

1. THE MELBOURNE DART RIOT

The Darts Invitational Challenge, an international tournament held in Melbourne, attracted international gawking in January 2015 during the finals match between Michael "Mighty Mike" van Gerwen and Simon "The Wizard" Whitlock. The dart players weren’t making a scene, though: Rather, hundreds of spectators, many of them drunk and in costume, began throwing plastic chairs as they watched (pictured above). The reasons for the fight remain unclear; footage and photos show police trying to control adults dressed as Oompa-Loompas, numerous superheroes, and, in one instance, in a ghillie suit (heavy camouflage meant to resemble foliage).

2. THE LEICESTER BALLOON RIOT

In 1864, balloonists were the great daredevils of their time, and a major draw for eager audiences. That summer, Henry Coxwell, a famous professional aeronaut, was set to make an appearance for 50,000 paying ticketholders in Leicester, England. Unfortunately, a rumor spread that he hadn’t brought his biggest and best balloon to the event. After heckling from the crowd, Coxwell deflated his balloon, and attendees rushed it, ripping it to shreds, setting it on fire, and threatening to visit the same fate on Coxwell. Rioters even paraded the remains of the balloon through the streets of town, which briefly brought residents a new nickname: Balloonatics.

3. THE TORONTO CLOWN AND FIREFIGHTER RIOT

Toronto was still a pretty rough place in the 1850s, but not so rough that the circus wouldn’t come to town. As it turns out, circus entertainers were also a tough lot back then, so when a group of off-duty clowns spent an evening at a brothel popular with the city’s firefighters on July 12, 1855, tensions came to a head. Accounts differ as to who started the fight, but after one firefighter knocked the hat off a clown things escalated into a full-on rabble intent on chasing the circus out of town. Only the mayor calling in the militia put an end to the uproar, an incident Torontonians credit with kicking off much-needed local police reforms.

4. THE BELGIAN NIGHT AT THE OPERA RIOT

Charles Soubre, Wikimedia Commons // Public Domain

Not many nations can claim their independence started with an aria, but for 19th-century Belgians sick of living under Dutch rule, an opera was just the right fuse for a revolution. To honor the birthday of King William I of the Netherlands, a theater in Brussels put on La Muette de Portici, about an uprising in Naples against Spanish rule. One song, "Amour Sacre de la Patrie" ("Sacred Love of the Fatherland"), aroused nationalistic passions so much that after the opera ended, the crowd began destroying factories and occupying government buildings. That was August 25, 1830; Belgium declared independence on October 4.

5. THE NEW YORK DOCTORS' RIOT

Hamilton fans, take note: Everyone’s favorite Founding Father once tried to quiet a mob bent on burning corpses. For centuries, anatomists and medical students relied on gruesome means to learn about the human body. Cadavers for dissection class often came from grave robbers, since the corpses of executed criminals were the only legal source—and they were in limited supply. In New York in 1788, rumors abounded that medical students were digging up paupers’ graves and black cemeteries. When one mob came after the doctors responsible, Alexander Hamilton tried, and failed, to restore the peace. The crowd swelled to about 5000 before militiamen intervened, leading to up to about 20 deaths.

6. THE BROWN DOG RIOTS

The Anti-Vivisection Review, Wikimedia Commons // Public Domain

Riots against the dissection of dead human bodies were not rare in the United States at one time. But on December 10, 1907, a thousand Britons marched in support of vivisection, or surgery on live animals. At the center of the controversy was a small terrier allegedly vivisected without anesthetic in 1903 during a class at London’s University College. Animal rights activists erected a statue to the dog in 1906, which enraged area medical students, and protesters tried to destroy the statue using crowbars and hammers. For the 1907 march, 400 mounted police were deployed to contain marchers. The statue became such a flashpoint (and an expense to local authorities) that in 1910, it was removed and melted down.

7. THE EEL-PULLING RIOT

Palingtrekken (eel-pulling) was once a popular contest in Amsterdam, in which a writhing eel was suspended over a canal and hopefuls on boats would leap to snatch it as they passed beneath (usually landing in the water instead). However, “eel-pulling” was also illegal—the government deemed it a “cruel popular entertainment”—and in July 1886, police intervened at a particularly large gathering in the city’s Jordaan district. Civilians threw stones and bricks at police, and when some nearby socialist protestors joined them, a riot broke out that lasted for several days. The army finally intervened and opened fire on the protestors. All in all, 26 people died and 136 were wounded, but somehow, the eel itself at the center of the riots was allegedly saved and auctioned off in 1913.

A version of this story originally ran in 2015.