I had my bike attached to a bicycle rack just beside the frontage of a bicycle shop with a low-end cable lock. I'd forgotten the u-lock and had popped in to the shop to pick out a more-than-temporary lock.

I got them to detach the lock from the cardboard as it was going to be used straight away. When I came back out, a black guy was hunched over my bike with his arms industriously pumping away. I called out, he saw me and started to run. In a reflex motion more than anything else, I threw the Abus Granit at him.

Clongggg! A hit right in the noggin. He fell over, hit his head again on the pavement after that with a thud that I could actually hear from several meters away, unsteadily picked himself up and staggered away, falling over several times but still in a hurry.

I was sidetracked by a new fork while in the shop, but I decided not to look at it. Had I been doing that, the guy would have sawn through the lock.