Sperms start out as a cluster of interconnected cells. In the final stage of spermatogenesis, a structure called an "individualization complex" enables sperms to separate from each other, so they can mature into individual cells. An unknown mechanism provides the energy for this to happen. This image shows three "individualization complexes" (in red) working in the process of separating sperms (in green). In the image, you can almost feel the strong force coming from the "individualization complexes" as they travel along the elongated sperm bundles (from right to left), leaving behind mature, fully formed sperm — which can be seen if you look closely to the right of the red structures.