An old one from Isaac Asimov As is well known, in this thirtieth century of ours, space travel is fearfully dull and time-consuming. In search of diversion, many crew Members defy the quarantine restrictions and pick up pets from the various habitable worlds they explore. Jim Sloane had a rockette, which he called Teddy. It just sat there, looking like a rock, but sometimes it lifted a lower edge and sucked in powdered sugar. That was all it ate. No one ever saw it move, but every once in a whil…