This thick black-gray slime grows around the base of some mushrooms deep underground. It has a texture similar to that of cottage cheese; maybe a tad chunkier. Dusk Cheese is harvested by those who dwell deep underground and used as a spread to flavor breads and, occasionally, meats. Most "Top-Siders" consider it absolutely disgusting.
When specially prepared is can be used in a sheath to help a weapon glide out more easily or even, under certain circumstances, grant someone who ingests it limited enhanced night-time visibility at the cost of some mild nausea.