property of the substance is that it does not exist within the boundaries of a crystal sphere, to the degree that it cannot be brought into a crystal sphere by any known means up to and including the direct will of deities. Every crystal sphere floats in the phlogiston, very slowly bobbing up and down over time. Travel between Crystal Spheres is facilitated by the formation of "Flow rivers" — sections of the phlogiston which have a current and greatly reduce travel time. Travel through the "slow flow" (i.e. off the Flow rivers) is possible, but very dangerous. The Spelljammer The Spelljammer is a legendary ship which looks like a gigantic manta ray, and houses an entire city on its back. All spacefarers (people who live in wildspace) have heard of the Spelljammer but very few have ever seen it themselves. It is this ship that gives its name to "spelljamming", "spelljamming helms" and anything else connected with spelljamming. The ship has been reported to have been seen in countless spheres for as long as records go back. Even some groundlings (people who live on planets that have very little or no commerce with spelljamming communities) have legends about it. There are hundreds of conflicting legends about this ship, and a mythology has developed about the ship that is similar to the legends surrounding The Flying Dutchman. As a living thing (although it does not consume any matter, it does absorb heat and light through its ventral (or under) side and uses them to produce air and food for its inhabitants), the Spelljammer has a complex life cycle and means of procreation. Normally the ship has no captain and wanders the cosmos seemingly aimlessly. When the Spelljammer has a captain, obtained through another complex process, it will create Smalljammers (miniature versions of the Spelljammer) that go forth as its spawn. Apparently there can only be one Spelljammer at any one time. One Smalljammer will mature into a full Spelljammer ship if its predecessor is ever destroyed. Races Alien races inhabiting the Spelljammer universe included humans, dwarves, xenophobic beholders, rapacious neogi, militant giff (humanoid hippopotami), centaurlike dracons, hubristic elf armadas, spacefaring orcs called "scro", mysterious arcane, the Thri-kreen insectoids, and bumbling tinker gnomes. Illithids were another major race, but were presented as more mercantile and less overtly evil than in other D&D settings. The Monstrous Compendium series added many more minor