Sometimes walking through a moldering old crypt can be a pleasure. With the smell of bone dust and ancient burial wrappings, almost like a library. Certainly as quiet. Until you step in a patch of Choo Mold.
The PCs find a small green glass bottle, something can be seen writhing within the smoked glass. If the PCs open the bottle a repulsing form of life will pour forth and grow in size. A genderless beings of soft pliable purple flesh towers before the PCs, it has no detail, no distinguishing characteristics except for a narrow slit for a mouth that holds rows of inwardly curving teeth.