The little green man from Mars hid himself behind his total invisibility vortex. Unseen and unheard he observed the scene unfolding in front of him.
The guards lined up the prisoners, then instructed them to crouch on small tables at one end of a small indoor lake. The chief officer made a strange one armed salute to a side kick who sounded a beep. Upon this signal the prisoners hurled themselves into the chemically polluted water and started to labour along a long black line by moving their arms and legs.
Those who had committed the worst crimes were forced to make 30 laps of the lake before some other guards pressed buttons allowing them to stop. The less evil ones were released after only 8. Wave after wave of punishment was unleashed on the prisoners – some even came back for more. None of the prisoners were allowed to eat but the guards had ample supplies delivered to them on plates.
Mooseglurg had seen enough. In a puff of invisible smoke he engaged his hyperspace drive and zipped home to Mars.