Slime mold guessers are right! This is a slime mold — aptly-named “Dog Vomit Slime Mold” (Fuligo septica). Slime molds are not plants, animals, fungi or bacteria. This stage of a slime mold’s life cycle is called a plasmodium, which is essentially one giant cell with millions of nuclei. The plasmodium moves by slowly flowing over the ground, gradually engulfing and consuming fungi and bacteria that are present on decaying plant matter. You often find it on mulch that is regularly watered. Dog Vomit Slime Mold is harmless to people, pets and plants. In fact, it is actually edible. In some parts of Mexico people scramble it like eggs (and call it “caca de luna”).