It appears, based on the pictures, that you have what is called a "slime mold" on your turf grass. Although it's not very attractive, it is relatively harmless to the turf. You can remove it by mowing or raking it off the blades. Simply let the area dry out, and the problem should subside. There are really no chemical recommendations for the issue. Simply remove it from the tissue, and you should see it go away fairly quickly.