LOL maryjanemama, there might be. I've read a few Stephen King boks and never heard of something like that, but it sounds like a Stephn King story...

There was an X Files episode once about a travelling circus that had a freak show, one guy had a conjoined twin on his stomach, but it was tiny and deformed, and at night it would pull itself off of its twin and hobble around on his arms and eat people :S