A type of tumor, also known as "scum tumor" or "sebaceous cyst." It often arises due to the congealing of phlegm and stagnation of qi. Commonly occurring on the head, face, neck, back, buttocks, and other areas, it can be as small as a bean or as large as a chicken egg. It grows slowly, is soft rather than hard, with a pale red skin color, and can be moved when pushed. The top often has a small, slightly blackened opening from which a foul-smelling, tofu-like substance can be squeezed out. It is now referred to as a sebaceous cyst.