caltrop
noun
°A small, metal object with spikes arranged so that, when thrown onto the ground, one always faces up as a threat to passers-by.
°(colloquial) The starthistle, Centaurea calcitrapa, a plant with sharp thorns.
synonyms: caltrap, galtrop, cheval trap, galthrap more» , galtrap, calthrop, crow’s foot, puncturevine, cathead, yellow vine, goathead, burra, gokharu, bindii