Caltrops rest on three prongs, with one prong sticking straight-up, when it is laying on the ground. An unfortunate person pursuing ninja might get nail striking up through his shoe and into his foot. Again, this weapon didn't destroy, however it slowed-down pursuers. See more realninjagear.
Often ninjas used substances that acted like pepper spray. They are able to fling it in people's providing, producing pain and eyes ninja time for you to escape. Some ninjas knew making substances that caused little surge, like firecracker. Everyone would be startled by this long enough for ninjas to perform their mission.