Fungus-like protists have characteristics of both unicellular and multicellular life forms. They are often found on decaying organic matter, and reproduce by creating spores. They include slime molds and water molds. Slime molds are further divided between cellular slime molds and plasmodial slime molds.
Cellular slime molds live in freshwater and moist soil, and spend much of their time in an amoeba-like feeding stage. When food is scarce, many individual cells clump together in a slug-like form and move in a coordinated fashion. Once they are ready to reproduce, this slug-like form stops moving and transforms to create a fruiting body that releases spores.
Plasmodial slime molds don't live as separate cells, but instead as a large single mass of cytoplasm with many nuclei known as a plasmodium. They release spores as a way of surviving during times when a plasmodium could not. Plasmodial slime molds creep slowly from place to place, feeding on decaying material.
Water molds form branching filament structures with cellulose cell walls. Some species feed on dead plants and animals, but many are parasites. Aquatic species often parasitize fish and grow on their gills. Land species often parasitize plants. A water mold was responsible for the Irish Potato Famine.