We are trying to identify this.
It is about a 1/4 inch in size.
It looks like the seed of puncturevine, Tribulus terrestris.
What would be the result of a person eating this ?
If you ate this off the ground, it would hurt. Goathead on the plant while still green would hurt a bit less.
Some say that there are medicinal properties attributed to the seeds, per the link below, but I say if you have it on your property, kill it as I'm a bicyclist, and speaking for all of us, it is a scourge.
Here is a link that might be useful: Wiki on Tribulus t.