Stuff like this -[Slime mold](https://empire-s3-production.bobvila.com/articles/wp-content/uploads/2021/10/iStock-518732516-dog-vomit-slime-mold-650x432.jpg) [What is slime mold](https://www.discovermagazine.com/planet-earth/what-is-slime-mold) EDIT: That particular doozy is nicknamed dog vomit slime mold :-)

They are well.. Mold. They are interesting though. This one kind of look similar to the pic and what you described. https://en.wikipedia.org/wiki/Fuligo_septica Main page: https://en.wikipedia.org/wiki/Slime_mold