The Pelomyxa or Chaos chaos is a very large protozoan and belongs to the Phylum Sarcodina.

It has an ever changing shape and is approximately 1000-5000µm long. This is 1-5 mm! It can easily be seen with the naked eye. Shown in the picture at the left is a Paramecium for size reference.

The Chaos chaos can be ordered from science supply companies but it is a fragile protozoan and does not survive well in the classroom.

They can sense light and move away from it. It reproduces by plasmotomy, forming two to six daughter cells. Chaos chaos feed on Paramecium.

At lower left we see a Chaos Chaos enveloping a Paramecium. Many of the dark spots inside the protoplasm are food vacuoles. They hold undigested food, usually composed of ciliates. Look closely at the lower right of this picture you can see another Paramecium, totally enclosed.

Below is Chaos amoeba crawling on a glass slide at approximately 250x magnification. Video courtesy of Win Aye.