Tribulus terrestris

Like a thumb tack and
nasty to find in the yard,
no one likes this plant!

~carliewired

We call them goatheads or ramsheads. We hate to find them on the soles of our shoes when we've ventured out into our yard. They have prongs about a centimetre long. We are careful to check our shoes before coming inside. One does not want to find these on the floor in one's bare feet. They are sharp enough to puncture a bicycle tire. Nasty! Nasty!

People go to extremes to rid themselves of this invasive weed. I've seen suggestions to pour boiling water over them, spray them with chemicals and/or fry them with a flame-thrower.