From Introduction:
Buying and Selling
They come from across time and space itself, clacking their many pink and violet legs across the ground, warbling their bulbous, segmented chins, and chattering their crooked, nasty teeth. From behind those same yellow chompers come their demands, for they are merchants, these horrors, and they buy and sell all manner of bizarre and arcane implements, from the tears of murdered angels to the memories of ancient empires, from the hardwoods of the elemental planes to the treasures of empires that have not even yet been founded.
Their planar nature is obvious to those with eyes—they care not for the pull of gravity, bringing their own with them wherever they go, even floating through the air itself. Their minions, gathered piecemeal from planes unnumbered, are perhaps not so lucky, but the Mung Mung do not seem much to care.
Beware the Mung Mung merchant’s arrival until you are certain it has not fixated its attentions upon you. These merchants trade in many things, but when they find something of immediate interest, they will not take “no” for an answer. They stop at nothing to procure whatever (they say) they must have—even if what they want are your limbs and memories. On the other hand, if one can find a Mung Mung merchant in a pacific state of mind, one can make exceptionally favourable trades. For they do not see value the way we do. Gold means next to nothing, while the sand of a particular beach might be worth more than its weight in diamonds. Ancient magical items can be had for the price of a few flowers, or an unruly neighbour, or best of all, unwanted and painful memories!
Yes, indeed, is it not wondrous? Come, friend! Ignore their offputting and otherworldly appearance and join the Mung Mung merchants in the sphere of trade and commerce. Are you not savvy? Do you not recognize a deal when you see when? Do not be afraid, hand your weapons to the market wardens. Yes, that’s it boys! Get him! What a trade we’ve got our hands on now!