I no longer have the crab monster on my map. I have had this issue for a very long time (maybe 8-9 months) but never thought much of it. I just actually just thought the crab monster was supposed to disappear once you reach a certain level. My wife recently started playing and now is starting to advance but her crab monster is stil there. Not sure if it's known or how many others have the same issue but I thought I would report it.