caltrop

Caltrop is a type of small, spiky device or multiple branched object with spikes or needles on the ends of its branches. It has been used as a military weapon and obstacle for thousands of years. In ancient warfare, caltrops were made as a sharp four-pronged device, sometimes made from metal or wood, to inhibit the movement of both horseback riders and horses.

The caltrop's use can be traced back to ancient China, Greece, and Rome. In Asia, caltrops were used as an anti-horse measure, in the countryside of China during the Western Zhou period, around 1046 BC. Sparta's army in ancient Greece is said to have created them in the 8th or 9th century BC. A Roman architect in the works of Engineer Frontinus relates to an ancient mass of hedgerows that included a military caltrop as an obstacle against enemy cavalry.

A more modern modification of the caltrop is the "dragon's teeth," or "caltrops," a pyramidal steel obstacle for automobile and tank obstacles. They were first used in the Middle East during the larger invasion by Britain in World War I.