A comic book is a literature item.
A comic book reduces the player's level of unhappiness, stress and boredom. Once used it is effectively 'consumed' and removed from the player's inventory.
A comic book can be used as a fuel for a heat source, and lasts for 15 mins if done so.
It can be found in lockers, library counters, and small tables.
From newitems.txt (Project Zomboid directory/media/scripts/)
Weight = 0.1,
Type = Literature,
UnhappyChange = -20,
DisplayName = Comic Book,
StressChange = -20,
Icon = ComicBook,
BoredomChange = -30,