Nest in sunroom
This is not an insect nest, but rather the sporangia of dog vomit slime mold (Fuligo septica). Slime molds are not fungi, but are more closely related to certain seaweeds and amoebas. Dog vomit slime mold lives in damp areas where it breaks down dead plant material, so is commonly found in mulch, under bushes, and other areas around the exterior of homes and buildings. When conditions get to dry, slime mold form sporangia in order to produce spores that can disperse to more suitable locations or wait until conditions become moist again.
Interestingly in this photo, you can see where the slime mold apparently came up through a crack, moved about a bit, and, "deciding" it was too dry formed a sporangia.
Slime molds aren't dangerous. You can scrape the sprangia off with a stiff but flexible object and toss it outside.
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