"Witch's butter" in the forest: bright yellow slime best left untouched

"Witch's butter" (Fuligo septica) is a slime mold — an organism that is neither plant, nor fungus, nor bacterium. The bright yellow, foam-like mass appears on dead wood and soil in damp forests. Despite its unscientific name, the organism is biologically fascinating: it can move and "make decisions" without a nervous system.