While looking through a bit of floating pond debris, I encountered this enormous amoeba. I did a quick estimate and concluded that this cell was around 700 – 1000 micrometers long (for reference, 1000 micrometers = 1 millimeter, 1/10th of a centimeter). This amoeba is likely multinucleate and from the genus Pelomyxa or Chaos.
Below: This photomicrograph was taken at around an 80x magnification.
Below: This amoeba was found in a sample of pond sediment. It is likely a different species than the amoeba shown above.