Octopus joubini?
 

Does anybody have information on O. joubini? Seems like a pretty cool little critter, and given its size, I could probably get away with feeding it clams from an asian market (Wikipedia: "It is able to bore into the hard shells of small clams, crustaceans, or other creatures"), and/or $1 hermits and/or amphipods, in a small tank like a 20H or 20L. At least...assuming that I could actually get one of the actual species that is.

I had a pair years ago; they're nocturnal and small. Only saw them a handful of times at night, with a red flashlight.