hicth hiker id

Get this nudi-like hitchhiker from TBS live rock. Seems to appear more often after lights out. Mostly transparent, a little green/brown. Have two very very long stringy tentacle extending from its front and end, the stringy tentacle is very thin and has a comb-like structure. Good or bad...

So, I was looking at my tank just a little bit ago and I say this little white crab on one of my snails. So as any concerned tank owner I looked up what it was and found no use full info. So I have come to all of you for help to find out what it is and if it is a good or bad crab. Here’s a...

I’m thinking it might be a slug or some sort??