This organism swims without flagella at speeds up to 25 µm/s -- see project . When cells hit a glass wall, they pinwheel, rather like a tethered cell. The first movie shows swimming. The second movie (at higher magnification) shows pinwheeling.
Waterbury, J.B. et al. A cyanobacterium capable of swimming motility. Science 230, 74-76 (1985).