Erich
the old Sage
It appears to be slime mold, and why would it reproduce there is the question. Removing it was your best bet, either by raking or rinsing off. In any case it is gone so just watch the area. thatching of the lawn is good so nothing else will try to affix it self in the spot. Warm-hot weather without rain will eliminate the problem and the mold is associated with high humidities as we discussed
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