Sometime in the summer months during the years from 1993 to 1998, my friend and I saw what looked like a gamma-ray burst (or what looked like an artist's impression of it). It looked like a star that got very bright (within a few seconds) and we saw what looked like a line shooting out from the sides of it that spread across our field of vision. All this happened in less than 10 seconds.
I can't confirm when it was any more exactly than that, unfortunately, as we were walking near my friends house at night in the summer, as we did hundreds of times in those years.
According to Wikipedia, the first naked-eye brightness gamma ray burst happened in 2008, so I imagine that's not it.
What could it have been?