I googled why snakes shed skin and this is what I found out, if just looking at it wasn't scary enough!
Put simply, snakes shed their skin because it doesn't fit anymore or because it's old or worn out. When snakes grow, their skin does not, so they outgrow it. When this happens, they shed their outer layer of skin. ... Snakes also often shed their skin before reproduction or after giving birth.
I found this by my driveway, not sure if someone put it there to scare me or the snake decided it was time to try a new "look" right there.