If you can't see them...
then they can't see you right?
I found this Texas Spiny Lizard half-way burrowed under a rock in one of our beds today. I checked on it about 15 minutes later and it was in the same position. I tapped its tail and it twisted around, looked at me and bolted. I guess it thought it was in far enough to be protected :D
Shame on me for interrupting a wonderful siesta!