Mystery of well-armed seed SOLVED

Have you even seen one of THESE? James is holding its curved tip. When I was outside, working today, I felt something sticking my arm through my long-sleeved top. 

Yikes! This is what I found!

UPDATE FEBRUARY 24, 2012 

Master Naturalist Edie Z. identified this seed for me! 

"I knew I had seen this seed, couldn't remember why it stuck in my mind," she emailed me today. "So after doing some research on the internet and then checking my Texas Wildflower book, I am pretty sure the seed with the little corkscrew on the end comes from the plant called stork's bill (Erodium texanum). The geranium family, of which this is one, has several members that have this type of seed. The end coils when the air is dry and then uncoils when the humidity rises. Neat way to disperse. Problems occur when this seed gets in the fur or wool of an animal and then works its way under the skin." 

UPDATE TO THE UPDATE MARCH 2, 2012
This is Erodium cicutarium, not taxanum. See blog post March 2, 2012.