WTF is THIS???

Calling all my people out there who might know anything about Texas lawn pestilence! I noticed this...weird crap this morning.



I fear a fungus. It looks like...ash or something similar. And there are several spots of it around the front. Just the front, of course. Not the back or the sides where we have some sort of "undesirable" (but much more hardy) grass.



Any ideas out there? What might it be? What will it do? Should I just treat the entire front lawn with diesel fuel now, burn it to the dirt and lay down astroturf?