This type of military anti-cavalry obstacle is usually called "garlic" in Russian

This type of military anti-cavalry obstacle is usually called "garlic" (chesnok) in Russian. Metal caltrops consist of spikes pointing in different directions, and they were scattered in great quantities along the presumed path of the cavalry. These strewn spikes could stop infantry, elephants and war camels alike. The obstacle has been known since deepest antiquity, and at various times such spikes were made of bronze or even bone. In a somewhat reinforced form they were used in the twentieth century too, now against car tyres. During the Battle of Borodino more than 70,000 poods of "garlic" were used against the French cavalry