Vorticella is a single-cell bell-shaped ciliate that attaches to material with a very thin, highly contractile stalk. Upon contact or unexpected movement, Vorticella contracts faster than can be captured by standard videeo equipment.

A ring of cilia around its opening moves in unison to create a vortex in the surrounding water, bringing bacteria and algae into its oral opening to feed. While Vorticella can often be found alone, it can also be found in clusters.