Dungeons are always described by locals as dangerous, spooky, and unlucky places. On Ezzin, sometimes all three are literally true. Some say that the Underworld is the resting place of the dreaming gods, and that all dungeons are connected through their dreams. In these places sometimes the normal rules for reality just don't apply.
To make one dungeon particularly "unlucky", I've decided to use the Die Bag of Fate rather than impose a penalty to die rolls. Anytime someone (including myself) was making an attack or rolling a saving throw they would not roll as usual, but instead they would be passed a die bag and told not to look inside, take out only one, and roll it.
Success is determined by the color of the object chosen.
First Color = Fully successful (Use crit chart)
Second color = Successful (Roll damage like a normal hit)
Third color = Minimal Success (glancing blow, only 0-1 damage)
Forth color = Miss
Fifth color = Fumble (Use fumble chart)
Stones and tokens are stuck at their color, but dice can move up to the next best outcome. The die is rolled and any applicable bonuses are added. If the total is equal or greater than the number of sides on the die then the outcome has improved by one step. For example, a PC attacks a monster, pulls a Red d4 and rolls a 3. The red means that the attack missed, but if the PC was determined to have a bonus to attack (magic weapon, dex bonus to thrown weapon, ect.) a bonus of +1 or more would make the roll equal the number of sides on the die (4) and the attack would be moved up to "Minimal Success".
At each level of the dungeon, any number of dice in the bag could be changed to represent the ebb and flow of the tides of luck. Special tokens or unique stones can also be added to represent random events, wandering monsters, traps, and more.