Diuresis is a period-90 oscillator consisting of two bookends being hassled by oscillators or stable catalysts. The original oscillator was found by David Eppstein on October 11, 1998, and was hassled by pentadecathlons. With a minimum population of 66 cells, this is still the smallest known form of the oscillator in terms of cell count. Later that same day, Dean Hickerson replaced the pentadecathlons with the still life arrangement. The form below shows two still life arrangements, one with the minimal population (left) and one with the minimal bounding box (right).
The name is due to Bill Gosper, who compared the bookends to kidneys.
Without any sparkers or catalysts, the bookends still appear 45 generations later as they do in the actual oscillator, but with boats as junk.