Saw a documentary on Physarum polycephalum AKA "The Blob" last night.
It's a single giant cell.
Although it does not have a brain or nervous system, this organism is still capable eating, moving, learning and teaching.
It is neither an animal, nor a plant, nor a fungus.
It has been living in the undergrowth for more than a billion years.
In its natural state, it feeds on bacteria and mould (fungi). In the laboratory, the scientists give them oats flakes.