These pesky little soldiers are everywhere on the streets of Griffith! All it takes is to get one in the sole of your shoe (see image below for example) then to walk into another area with suitable soil (they grow in the driest of conditions) and it will set up shop ready to reproduce more fighters.
It's Caltrop! In some states it's a 3-corner jack it produces, or cats-heads in others but the talk is all the same; it's a pest!
But wherever I go it's on a dirt footpath, or in between the cracks of cement and it REALLY hurts when you step on one that you accidentally brought inside under your shoe.
What's the best way to get rid of them? It's not the only weed but boy, oh boy, they are super annoying!