Well, I'm not completely sure what happened but it might have evicerated (expelled it's guts). They do this when stressed but I can't imagine what could have stressed it 2 weeks after you received it.
If it's healthy then it will grow back a new digestive tract and be good as new in a couple of weeks. It may not move much in the meantime.
As a precaution I would remove it to a quaranteen tank but I'm considered conservative. I would at least check it a couple times a day to see that it's not falling apart (dead).