One scene confuses me.

It's been a while since I've seen this movie. There's a scene where Authur is alone in a room that is dimly lit by candle light and... something's shadow is cast across the room and you can hear tiny footsteps. Whatever the thing is, it's never shown and never appears again. But judging from the shape of the shadow it is very small and walking around upright on it's lower limbs.

Does anyone know what that strange thing running around on the floor was? o_O In a later scene we see a pool of blood on a bed with an odd monster coming out of it. I thought that this was the ghosts way of taunting Arthur with the memory of how his wife died. So maybe that thing walking around on the floor was some kind of 'ghost fetus' or something?