Your body is a crowded metropolis, a microbial Manhattan. Spirulina -a cyanobacteria- roams your intestinal streets like a finger- snapping gang of modernist dancers, populating your intestinal Gotham with teeny, pirouetting, highly choreographed floral cells in micro-tights; most of them part-time waiters. NASA has used Spirulina as a dietary supplement for astronauts. Here the dance metaphor ends.