Cycling fans are known for their enthusiasm, but with the good always comes the bad, and during Stage 2 of the Giro d’Italia on Sunday one fan put on a clinic in what not to do while watching a cycling event. Instead of cheering on the peloton as it passed, one man decided to mount his own bike and ride along with the large group of cyclists. The result? A huge, multi-bike pile up.

Trek Factory Racing rider Eugenio Alafaci took to social media after the leg, which was eventually won by Team Sky’s Elia Viviani, to voice his anger over the rogue fan.

“There are no words to describe the bull—- this moron caused,” Alafaci said on Facebook, adding that he wasn’t angry with race officials or police who set up the barrier between riders and spectators, but just the “jerk” himself.

According to the race doctor’s official medical bulletin (via CyclingNews.com), the crash affected 30 riders and blocked others who came up on the peloton from behind.

“I hope he hears all the talk about what he did and at least apologizes publicly to all of us riders,” Alafaci continues. “Stuff like this must no longer happen!”

While this level of irresponsible spectator behavior isn’t common, it’s not exceedingly rare either. In March, a spectator caused Australian cyclist Loren Rowney to crash after he grabbed her handlebars over the barricade in the sprint finish of the Molecaten Drentse 8 in the Netherlands. Others have been caught throwing tacks on the route in the Tour de France, or worse, spraying a rider with urine.

These incidents likely won’t stop, despite riders’ pleas, because it’s very rare that anyone gets punished for breaking the laws of common human decency when it comes to watching cycling.

“It is very difficult to do anything [about it],” Team Etixx-Quick-Step CEO Patrick Lefevere told Belgium’s Sporza.be (via Cycling Weekly). “If [Pieter] Serry (one of the 30 riders affected in the pileup) wanted to do something, then he had to submit a complaint against the unknown person on Sunday evening. But no-one has been able to identify or stop the perpetrator.”