Sometime in the late 1990s I was driving from Castlederg in Co Tyrone to Killadeas in Co Fermanagh on a road I'd never been on before. It was winter and dark, but not quite pitch dark as the sky was a very, very dark blue colour.
The road was rural, and there was nothing on it, and I was using main beam lights, so when I turned a corner and started uphill I was a bit surprised to see a large black triangle at the top of the hill against the very dark blue sky. (Back then on British motorways they used massive road signs for roadworks, possibly 2 metres high triangles with a scaled up version of the roadworks sign.) As I approached the top of the hill the triangle had moved and was now somewhere else and bigger. To my complete astonishment I could then just make out the shape of a black horse, pulling a black trap, driven by someone wearing a black coat and hat. No lights, no reflectors, nothing that wasn't black