Just a bit for everyone because everyone got it, here is additional information. Out here in California, we call it Whitestem Filaree,
http://www.ipm.ucdavis.edu/PMG/WEEDS/whitestem_filaree.html
As children, we used our finger nail, made a slot on one seed, and put another seed through the slot, creating scissors: we played with our Filaree "scissors." The dried seeds do burrow into the coats of animals. If a dog or animal was wiggly and uncomfortable, we checked for Filaree, and if we couldn't work it out with our fingers, often had to cut it out.