Aquired
2 red legged hermit crabs
2 turbo snails
2 money cowrie snails
Not much selection in snails. I hadn't heard of the cowrie snails and had to do a bit of research after purchase (I know slap my wrist).
Actually, as Donya says, many of the smaller ones are actually no worse than any other invert and can be kept rather peacefully in a reef, provided that it's well fed.
Sounds like a character. So far not seen him again. So still unsure if the external filter has sucked him in or not. No evidence in the canister, but it would've been mushed. Only time will tell.
I think I have another hitchhiker. Came down in the morning and something was pulling seaweed into the rock. Looked like crab legs but didn't see enough to ID.