Things are different on the Inner Planes. Oh, some bashers might say they're deadlier, or harsher, or just plain weirder, but this truth is, they're merely different. And on planes full of nothing but searing magmas, swampy ooze, glittering mineral, utter desolation, or life incarnate, is it any wonder that a body'd find creatures as alien as any the multiverse has ever seen? Things that eat color, leaving a victim fully transparent. Beasts that spread life like a virus, animating all things around them. Spirits that form bodies by forcing hundreds of smaller animals to act as one. It's enough to make a sod long for a pit fiend. Liven up any PLANESCAPE or AD&D campaign with the MOSNTROUS COMPENDIUM Appendix III, which features 128 pages of monsters that lurk on the Inner Planes, the Astral Plane, and the Ethereal Plane - some of the strangest and most inhospitable environments in the multiverse. Most of the critters are brand new, though a few old favorites have been updated. This book also provides a detailed look at the ecology of the planes in question, not to mention an appendix of inner-planar creatures that're more like animals than monsters. And, of course, all-new illustrations vividly bring each of these exotic beings to life.