In ordinary fluids, agitation fades on its own. But there are environments where rest is impossible: a solution with bacteria or molecular motors. Inside them, vortices and jets continuously boil — this is active turbulence. When a simple droplet was placed into this man-made storm, its fate was traced using computer simulation.

The droplet responds to the flows with sharp metamorphoses. Most of the time it is almost round, but suddenly stretches into a strip, like canvas under a squall. These jumps obey a scale-free law: there are many weak transformations and catastrophically few strong ones.

This chaotic trembling is a ready-made tool. By reading it, we can understand what’s happening inside a living cell, or design a microrobot to swim in turbulent environments. Similar processes govern magnetic reconnection in cosmic rays and the motion of the interstellar medium.