Myxomycetes are poorly known yet very interesting creatures. For decades they have been shuffled back and forth between the animal and plants kingdoms until recognized as separate creatures. They are not animals because they proliferate by spores. They are also not plants since they crumble around (an animal like ability) and fix themselves firmly to substrate only at the end of their life cycle. They don't produce their own food like plants but feed by 'hunting' (actually engulfing) bacteria and tiny bits of other organic matter, which is another animal like feature. The first stage in their development cycle, which is observable in the field, is called plasmodium. Earlier stages (from myxoflagellates, myxoamoebae, to zygote) are microscopic and can be observed only in labs. Plasmodium is a single giant living cell, a clump of protoplasm filled with thousands of cell nuclei, crawling around, eating bacteria and growing. Some of such plasmodia are the largest cells of living creatures known. In some species they can measure several meters across or weight up to 20 kg.