Pfiesteria piscicida
Pfiesteria piscicida is a dinoflagellate responsible for many blooms in the 1980s and 1990s on the coast of North Carolina.Its living cycle is extremely complex: scientists have found at least 24 different stages, spanning from cyst to several amoeba-like forms. The organism apparently moves through these different stages as environmental conditions require. However, new research from 2002 claims the cycle is much simpler than previously thought, and that the true Pfisteria is non-toxic (see external links).
Pfiesteria produces a powerful toxin, used to kill fishes, even relatively large ones. The toxin can also be carried in the air, as experimenters learned when cultivating the organism in laboratory.
Pfiesteria is named after Lois Pfiester, who researched dinoflagellates.