DANGER grass-like plant?

Question:ok so i went to the washington dc zoo and there was these plants. they look like crabgrass except its about a foot tall and thicker. i picked a piece and i rubbed it against my arm. it didnt hurt at first. then i realized that the grass had these tiny hooks/prickers on one side of it, and they made my arms get all cut and scratched up so now my arms look like i was attacked by a cat. do you know what this type of plant is called???

Answers:
pampas grass or sandspurs