Blackened grass??

A big patch of my grass turned yellow and died. I asked the gardener and he says he's seeing this around the neighborhood and last year in neighboring areas. Parts of the grass turned black, almost like streaked with oil, and look completely flat. I don't see any visual patterns to it. They think it might be a fungus, but are not sure. They also think it parts the raccoons like to dig it out and eat it, which I've seen dug out areas. Any ideas what this might be?