I've got a 75 gallon DT and have a collection of snails (which are frequently suicidal idiots) and some hermit crabs. One of the hermits was enormous - far larger than the fish. It was around 3" long. I have a six line wrasse, a silver molly, and a lawnmower blenny. Today I found the legs of the large hermit crab, but no body and no shell. What kind of hitchhiker would be able to do this?