From the website:
It's all about the thrill of combat . . . meeting worthy foes and murdering them by surprise . . . gleefully slaughtering their low-level minions . . . defiling the corpses . . . and, of course, TAKING THEIR STUFF.
The Munchkin Monster Guide contains dozens of foes for you and your comrades to slay, from the dreaded Gazebo and the surprisingly tough Potted Plant to the secretive Grassy Gnoll . . . and the really quite nasty Plutonium Dragon! Chock-full of great John Kovalic art, this book also includes creatures from the Unnatural Axe set, as well as lots of new and equally demented creations all detailed for use in Munchkin RPG games!