Yes wingnut, they disappeared but not in a mystical sense they became camaflauged by darkness/shadow. The first I had something dark on a hook on my door and it glided up and disappeared into the darkness of the item. I couldn't see it but knew it was there.
A few days ago it glided across my footstool, I leapt and left my seat quickly. I tried think logically, not wanting to acknowledge it was strange, I could only explain it as the tip of the cats tail passing by (as if) so I was apprehensive about turning to the catbed and sure enough he was fast asleep in it, I had to leave the room immediately it felt dense and wiered and I was scared stupid for sometime. So it remains unexplained.