While certain crimes are down at Oktoberfest this year, there have been more attacks with an unlikely, yet readily available, weapon: the one-liter beer stein. Some of the victims have been whisked away in ambulances with concussions and fractured skulls caused by fights involving the heavy glasses.

Police at the Munich Oktoberfest say crimes such as rape and theft are down this year but attacks with glass beer steins are on the rise.

The heavy glasses that hold one liter of beer are a symbol of the annual folk festival. But they can also be deadly weapons. And at this year’s fest they have already sent some to the hospital with serious injuries, such as concussions, and bleeding in the brain.

“At Oktoberfest it’s happening unfortunately more and more,” physicist Erich Schuller, of the Institute for Forensic Medicine at Munich University told SPIEGEL this week. “A stein like that weighs 1.3 kg (2.9 lbs) and thanks to the handle, it’s easy to grip, and that makes it an effective striking tool.”

Six Months to Life in Prison

So far this year there have been 32 injuries resulting from beer stein assaults, said Munich police spokeswoman Claudia Haas, up from 19 at the same time during last year’s festival. She said she expects the stiff sentences the perpetrators face will serve as a deterrent in future.