The fungi-like protists of Kingdom Protista comprise a group including slime molds and water molds. These molds are simple, unicellular organisms that are fungi-like in appearance and habitat, according to Cliffs Notes. By ingesting more complex organic matter, they act as decomposers. Like true fungi, they thrive in moist or wet environments.
Often displaying a slimy appearance for which they are named, there are two primary types of slime molds: cellular and acellular, explains CK12.org. During the feeding stage, both mold types form a mass that propels itself along, ingesting as it goes. Phylum dictyosteliomycota, a cellular protist, retains its cell walls as individual amoebas group together into a slug of protoplasm, while phylum myxomycota, an acellular protist, loses its cell wall, with the amoebas forming a mass with multiple nuclei inside of one cell membrane, called a plasmodium. Both types of molds prefer the damp environment of a rotting log or the forest floor.
Water molds are a separate group of primarily aquatic molds that act as parasites on land. For example, the water mold Phytophthora infestans caused a late potato blight and nearly wiped out the potato crop in mid-19th century Ireland, causing the Irish potato famine. Another water mold, genus Plasmodium, causes malaria in humans.