The Last Kids on Earth #6.5 Thrilling Tales from the Tree House(original) Max Brallier

The kids and their monster buddies are hanging out in the tree house, when Jack launches into an epic, totally-heroic, super rad story of one of his many post-apocalyptic adventures. Of course, after he's finished, everyone's eager to one-up his tale with a story of their own. Soon, Quint, Dirk, June and Skaelka, and even Globlet regale the group with sometimes outrageous, often hilarious details of their action-packed escapades during the monster-zombie apocalypse.