Having a Monster Manuel in your campsite will enable a drop off certain monsters that changes your avatar to their picture, temporarily. When used in the Boss Bat's lair against the Boss Bat, this allowed for a few more turns to fight the only other enemy, which dropped a lot of Meat for the relative level. Oh, and the areas where stars, lines, and pixels drop are otherwise unessential; even after all the revamps it's still possible that you won't have even unlocked them by the time you get to the door. These can range from skills and familiar IotMs producing extra items during the challenge path, to equipment IotMs being usable on the path regardless of regular restrictions. Certain pygmies in the remodeled Hidden City.