Looks like what I saw was a satelite launch fuel dump.
From this description: “The spectacular sight which keen South African sky-watchers were privileged enough to witness during the evening of Sunday the 18th of October, from approximately 8:45 to 9:30pm, – a spectacle resembling something out of a big budget UFO movie – turned out to be a great visual demonstration of experimental rocket science in action. From Hermanus to Jo’burg and even Nambia, reports started to flood into the South African Astronomical Observatory’s field station in Sutherland, as two bright objects were seen to be passing overhead from South-East to North-West at rapid speed. What made the reports so sensational was the repeated description of the leading object emitting bright, spiralling pulses of light which ‘looked like the kind of ripples you get when you throw a stone into a pond’ radiating over the whole sky.” Emphasis mine.
Pictures can be found here. It was quite a sight, and good to know what it was.
Hat tip: Mom, for finding the description.
