Floofquest: Hassle in the Quagmire by Lloyd Metcalf. Published by Fehu Games. This version was written for Swords and Wizardry and also includes a custom system to run the module. Softcover, perfect bound book.
From drivethrurpg -
Hassle in the Quagmire: An introductory Swords & wizardry and 5e adventure of wizard Floofy Familiars Trying to save their swamp!