The Maundbury Stain is an as yet unidentified species or species of silme mold fungus.
The Stain - as it is commonly referred to by residents - grows anywhere that dark and most conditions prevail. It is yellowish green in color, slick to the touch, and in some cases, bioluminescent.
The first mention of the Stain occurs in the annals of one of the early town fathers, John Seabury Quinn .
Even in this modern age, the Stain remains resistant to any current methods to control or eliminate its presence.
Recently, students and professors from Oxwain Occidental College' s department of abberant life sciences have been seen in town studying the Stain.