Science Nerd Alert

This is fascinating.
There is a cellular slime mold called Dictyostelium, which has one of the more remarkable life cycles in nature. Individual cells of Dictyostelium roam the forest floor as free-living amoebas, but if food supplies turn scarce, they congregate in huge masses and assemble themselves by the thousands into a much larger multicelled organism that looks and acts like a slug. The slug creeps about for a while, then settles down and metamorphoses into something that looks more like a fungus. The blob of cells sprouts a thin stalk that projects upward perhaps a quarter of an inch. Then other cells of the slug climb up the stalk and organize themselves into a ball balanced on top. The outer cells harden into a shell; the inner cells shrivel into dustlike spores. Eventually the shell cracks open and the spores are scattered to the wind. Spores that land in wet places change into amoebas and slither off to begin the cycle anew.

From Life Itself by Boyce Rensberger, Nigel Orme