The multi-nuclear protist Reticulomyxa filosa can be several millimetres in size and is divided into a stationary central area exhibiting wide protoplasmic streams and a peripheral area characterized by thin reticulopodia. The reticulopodia phagocytose nutritional particles where they are digested. Food limitation causes migration, often associated with plasmotomia. Several individuals can fuse. Under stress situations resistant forms are made.