I was looking at a cat sitting on a sofa across from me,. Suddently the cat looked over to a wall. I looked also. Damn, if there wasn't a faint turquoise-like dimly self-lit ball that came though the wall with dozens of slighly brighter lights moving around inside it. The ball moved very slowly across the length of the room. I glanced at the cat. It was also watching it. I thought, this can't be, but it seems to be happening. I considered moving to it and putting my arm out. I didn't. After a short while it finished moving across the room and out thorugh the wall on the other side as if it wasn't there. The cat then started cleaning itself as if this type of oddity happens all the time. I told my buddy, who rented the apartment, what I saw. He said that he sees weird things there all the time. I have no idea what that psudo light was, as light cannot pass through solid walls. This thing did. It makes me wonder what else is out there that we don't pay any attention to.