The strangest thing just happened. I was lying on my back on the floor (stretching out my back after a day spent mostly sitting) meditating with my eyes closed — and I had the impression that a large black dog entered the room. I knew it wouldn't attack me, it wasn't even particularly interested in me, but still I found it hard to close my eyes again. Eventually I felt that it was not in the room any more, and went on to finish the meditation.
But it still disturbed me so much that I had to walk around the apartment, stopping in each room for a moment, to feel whether it was still here. I think it's gone now.