This adventure is dark, weird, bizarre and quite wonderful, very old school and wacky. If you do not mind letting something a little outre loose in your campaign world, then give Lamentations of the Gingerbread Princess a try, I do not think you will be disappointed.
Lamentations of the Gingerbread Princess is a short module for the Lamentations of the Flame Princess weird fantasy RPG but compatible with most OSR style games (or similar games, I ran it with Pathfinder).
Sea of Stars RPG Design Journal 