Question
Our lawn has been taken over by a yellow fluffy cotton candy like fungus.  It is growing in different spots all over our lawn.  When it gets hot (upper 90s to 100s) it turns black/grey.  Once it is black/grey and you squirt it with a hose it is like ash and blows away.  What is this and how do I get rid of it?  This has been going on for about a month now.  K A - California

Answer
Sounds like someone's 'Fungus of the Month' from 1999, photographed here:

botit.botany.wisc.edu/toms_fungi/june99.html

and known as the 'Dog Vomit Fungus'.  Let's look at these Plasmodial Myxomycete Eumycetozoans.

First, they're NOT Molds.

They WERE considered Fungi.  No more.  Now they get their own 'Fungus-like' group.  Slugs and Garden Snails, Insect Larvae, Earthworms, even some Beetles LOVE to eat them.  If you drop a handful of, say, Manure nearby, the glob of Fungus begins oozing itself toward the manure.  When it's time, the Slime Mold dries itself up, shoots off a few trillion spores, and disintegrates into a mysteriuos pile of dust.

If it's not up there at botit.botany, perhaps you'll find yours here:

slimemold.uark.edu/educationframe.htm

Sounds to me like your Cotton Candy resembles what others call 'Dog Vomit Slime Mold', Fuligo septica.

Raking will disperse the spores and the Cotton Candy.  Drying out the Lawn or spraying the area with Vinegar or Ammonia may alter the conditions so extremely, they decide for themselves either to run down the street in search of greener pastures OR they simply decide life is not worth living.

Earthworms, Beetles, Slugs and other fauna actually don't mind having these organisms as a delicious snack.  If you see them in the area, protect it.

Water, as you have learned, will do nothing.  Bear in mind, this is widely considered to be quite harmless as Fungi like organisms go.

Keep me posted.  Thanks for writing.

THE LONG ISLAND GARDENER