Stentor is a type of single-celled organism known as a protozoan. It is often found in freshwater environments, such as ponds and streams. Stentors are shaped like a trumpet and can grow quite large for a single cell, sometimes reaching up to 2 millimeters in length. They are known for their vibrant blue or green color, which comes from the chlorophyll they contain, allowing them to perform photosynthesis. These fascinating creatures are filter feeders, using their hair-like structures called cilia to sweep food particles into their mouths. Stentors can also reproduce asexually by dividing, making them efficient at increasing their population in suitable habitats. Their unique shape and behavior make them an interesting subject of study in the world of microbiology.