Amoeba proteus, previously Chaos diffluens, is an amoeba closely related to the giant amoebae and a species commonly bought at science supply stores.
This small protozoan uses tentacular protuberances called pseudopodia to move and phagocytose smaller unicellular organisms, which are enveloped inside the cell's cytoplasm in a food vacuole, where they are slowly broken down by enzymes. Amoeba proteus is very well known for its extending pseudopodia. It occupies freshwater environments and feeds on other protozoans, algae, rotifers, and even other smaller amoebae. Due to phytochromes, A. proteus may appear in a variety of colors (often yellow, green and purple) under a microscope.