The SkunkLock bicycle lock aims to deter would-be thieves from stealing bicycles by making them throw up. 

Appropriately named SkunkLock, the lock was created to emit a smelly spray to thieves trying to cut it off. SkunkLock’s tagline: “The lock that fights back.”

San Francisco’s Daniel Idzkowski and Yves Perrenoud co-invented the medium-carbon steel U-shaped lock that holds three chemical gases they created. Yes, the gases are legal. They spray the thief once he or she cuts 30 percent into the lock, Idzkowski told The Guardian.

“It’s pretty much immediately vomit inducing, causes difficulty breathing,” Idzkowski said. “A lot of similar symptoms to pepper spray.” The spray has been tested on the SkunkLock inventors themselves and some brave volunteers, but has yet to be tested on a would-be thief. Idzkowski said tested at two feet away, “99 percent of people” found the spray vomit-inducing. He added that the spray is still “noticeable” and “unpleasant” at up to ten feet.

Idzkowski called SkunkLock a deterrent, but not a solution, to the reported 1.5 million bikes stolen each year. He told The Guardian SkunkLock could be picked, but it could take up to 30 minutes—long enough for someone to notice.

Check out the fundraising campaign for the SkunkLock here.