A hungry snake can be tricked into eating just about anything.
I have seen pictures of rat snakes found dead with golf balls in the gut......they like eggs and golf balls look close enough. I have also seen x-ray photos of a snake with a light bulb in its belly....probably same reason. Captive snakes have been known to half eat themselves too. You can find those pics or videos with a quick google search. Just cause a snake will eat something doesn't mean it is voluntary and a necessary part of their diet.