The Mold is a highly invasive microorganism that originates from a threshold known as the Mold Threshold found in the deepest level of the Research Sector of the Oldest House. No exact analogue for the Mold exists in this dimension, but it is superficially similar to a fungus or bacteria colony, hence its name. Portions of the Mold emit dense clouds of toxic spores or grow volatile buds that explode if disturbed, but its most dangerous trait is that it produces an enticing, sweet aroma to encourage humans to consume it. Once consumed, it propagates in the chest cavity and quickly subsumes the entire body, seizing control of motor functions. In short order, the infested person becomes a Mold Host, which is mindlessly driven to consume more Mold and attack any non-infested they detect. The source of the Mold is being designated Mold-1.
Dr. Raya Underhill was assigned to study the Mold after the Mold Threshold was discovered in the Oldest House. Although Director Zachariah Trench and the upper echelon of the Federal Bureau of Control considered the Mold to be hostile and ordered that it be contained and eradicated, Underhill recognized that the Mold was extremely adaptable, and its harmfulness was essentially because this dimension was being subsumed by it on a molecular level. Underhill believed that it could be harnessed in many beneficial applications, such as growing whole skyscrapers that were structurally stronger than concrete and steel, and was frustrated by her superiors' preference for caution.
Jesse Faden ventures into the Mold Threshold in the side quest Old Growth to collect Mold samples for Dr. Underhill, who uses them to make a pill that bestows immunity to the toxic spores and makes the sweet smell repugnant. Underhill then has Jesse find Mold-1, which Jesse kills, much to Underhill's disappointment. With the main source gone the Mold's spread into the Oldest House is slowed to a manageable degree, and Underhill continues her research. Ahti also puts Jesse to work reducing the Mold infestation in some areas.
Mold infestation locations
- Executive Sector
- Maintenance Sector
- NSC Coolant Pumps
- Containment Sector
- Medical Wing
- Correspondence: Executive Meeting Minutes
- Research & Records: Bureau Expenditures
- Research & Records: Mold Threshold
- Research & Records: Mold Autopsy