How is didymo commonly referred to in terms of its texture?

Didymo, often referred to colloquially as "rock snot," has a texture that is slimy and gelatinous, which is why the term "snot" effectively captures its physical characteristics. This freshwater alga can form thick mats on riverbeds and other surfaces, creating a gooey texture that resembles slime. The cellular structure of didymo contributes to its slimy feel, making the term "snot" an appropriate descriptor among anglers and environmentalists.

The other descriptors—slime, gel, and fungus—do not encompass the unique characteristics of didymo as clearly as "snot" does. While it may have slimy elements, especially when it accumulates in large quantities, "snot" distinctly conveys both the texture and the appearance that are prominently associated with this organism.