Ninja rocks are broken shards of spark plugs. Since they can quickly and almost silently fracture the glass windows on most cars, ninja rocks are increasingly the tool of choice in "smash-and-grab" auto burglaries. They have no traditional association with the ninja or ninjutsu, only being named such due to their "silent but deadly" function in burglaries.
Read more about Ninja Rocks: How They Work
Famous quotes containing the word rocks:
“The crystal sphere of thought is as concentrical as the geological structure of the globe. As our soils and rocks lie in strata, concentric strata, so do all men’s thinkings run laterally, never vertically.”
—Ralph Waldo Emerson (1803–1882)