Fake Snake food

So after the snake eel I posted about earlier buried himself, this thing popped up right next to it and took flight:

It's some sort of crustacean and appears to be probably a small mantis shrimp species. Thats its rear sticking out (it came out backwards) . Interestingly it only ran a foot or so before reburying itself and I have no idea whether the eel got it in the end.