About to molt?

Question
I have a purple pincher hermit and i was holding him today and i noticed at the back of his shell there was a black bubble type thing and im not sure wat it is but recently he changed his shell and ive only had hime for about a week is he going to molt and he has been eating a lot and sitting in the water bowl and digging a little bit and his eyes are kind of cloudy  

Answer
Hello Stephanie,
The black bubble you are talking about is the molt sac! You crab is going to molt very soon! The crab should be digging under the sand soon! WHen it does...leave him alone...the crab will come up on its own in a few weeks
! Depending on its size it could take a month ! Just make sure your humidity is at about 75 to 80%! Good Luck and happy crabbing!