Grass-like fungus appears similar to:
|Grass-like fungus crunches underfoot.|
Grass-like fungus is a vital part of the dungeon ecosystem replacing the role of surface grass. It fulfills similar ecosystem requirements as grass would such as being stepped on by adventurers and serving as food for dwarven yaks*.
Grass-like fungus is flammable. For this reason it is one of the primary features to pay attention to when using a potion of Incineration or a staff of Firebolt. One vault key trap involves a room full of fungus which is set aflame by a sputtering torch when the key is taken.
Grass-like fungus does not make you less stealthy for trampling on it.
There are other similar forms of fungus in the dungeons as well:
*The game brogue does not contain yaks.