Krähenfuß Duits WW1 (Caltrop german WW1)

A caltrop also known as caltrap, galtrop, cheval trap, galthrap, galtrap, calthrop, crow's foot is an antipersonnel 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 (for example, a tetrahedron). Caltrops were part of defenses that served to slow the advance of horses,  and human troops.  In more modern times, caltrops are used against wheeled vehicles with pneumatic tires.