A mantrap is a mechanical physical security device for catching poachers, art thieves and other trespassers.
They have taken many forms, the most usual being similar to a large foothold trap, the steel springs being armed with teeth which meet in the victim's leg.
In 1827, they were made illegal in England, except in houses between sunset and sunrise as a defence against burglars.
Mantraps that use deadly force are illegal in the United States, and in notable tort law cases the trespasser has successfully sued the property owner for damages caused by the mantrap.
As noted in the important American court case of Katko v. Briney, "the law has always placed a higher value upon human safety than upon mere rights of property".