SAC-BACK - The periphery of the sprawling 'Amoebic Sea' is a bleak and inhospitable region. As the sea has been receding its margins have left a flattened landscape, the 'Sea's' floor, as it were. Sac-backs roam these featureless wastes, walking with their awkward, three-legged gait from one group of buried females to the next. At each harem they will stop to either share their sack-stored food with their inert mates through their extended proboscises or mate with them in one of the more bizarre procreation rituals on the planet.

The weird region around the Amoebic Sea seemed to me to be the perfect place to push the envelope in terms of designing stranger creatures. Also, when I began to conceive the Sac-back, I was nearing the end of my personal design odyssey and wanted to make sure that I had enough really odd creatures in the book. This creature is really an amalgam of biological principals: the horn-bill's imprisoning of its mate, the camel's fat-storing hump, the manner in which cuttlefish touch each other with their tentacles, all of these ideas found their way into this animal.