It's a slime mould, often commonly known charmingly as Dog Vomit slime mould - its actual name is Fuligo septica. It appears usually during very damp weather, or in damp areas, and is likely to be seen on anything woody, including wood chips, though it can sometimes appear in lawns. It will just disappear as the area dries out and is not a threat to any planting you have, it's just not pleasant to look at. Further info here http://midwestnaturalist.com/fuligo_septica.html

It's a slime mould, often commonly known charmingly as Dog Vomit slime mould - its actual name is Fuligo septica. It appears usually during very damp weather, or in damp areas, in spring/early summer and again in fall, and is likely to be seen on anything woody, including wood chips, though it can sometimes appear in lawns. It will just disappear as the area dries out and is not a threat to any planting you have, it's just not pleasant to look at. Further info here http://midwestnaturalist.com/fuligo_septica.html