Calthrop

A calthrop (also known as caltrap, caltrops, or crow's feet) is an area denial weapon made up of two or more sharp nails or spines arranged in such a manner that one of them always points upward from a stable base. Calthrops are designed to impede the movement of personnel or vehicles by puncturing feet, hooves, or tires.

Etymology: The word "calthrop" is believed to derive from the Old English "calcatrippe," meaning "foot-trap," influenced by the Latin "calx" (heel) and "trippa" (entrails, intestines), possibly alluding to the pain caused by stepping on them.

Construction: Calthrops are typically constructed from metal (iron, steel, or even hardened plastic in more modern versions). They are often tetrahedral or octahedral in shape to ensure a point always faces upwards regardless of how they land. Simple calthrops can be made by bending a single piece of wire or welding together multiple spikes.

History: Calthrops have a long history of military use, dating back to ancient times. They were employed by the Romans (who called them "tribuli"), Greeks, and other ancient armies. They were particularly effective against cavalry, elephants, and infantry formations, disrupting their advance and causing casualties. Calthrops continued to be used throughout the medieval period and into the early modern era.

Modern Uses: While less common in modern warfare, calthrops still see some use. They are sometimes employed by law enforcement for riot control or vehicle immobilization. They are also occasionally used by civilian protestors as a form of passive resistance or disruption. Their use is often controversial due to the potential for causing serious injury.

Legal Considerations: The legality of using calthrops varies by jurisdiction. In many places, their use against civilians or in a manner that could cause serious harm is prohibited. Their sale and possession may also be restricted.