Ah, I suppose I should have emphasized that it wasn't added merely to act as a cliffhanger! The bulb-- and what's inside of it-- were originally going to be introduced near the beginning of the next layer, so if you can believe it, this has actually been planned, as a narrative element, reasonably far in-advance. I'm just sliding it in a little earlier, here... To build tension!
As far as what it is goes: "Alien" is an interesting interpretation, but certainly more science-fiction than what I'm ultimately angling for. I'm hesitant to explain exactly what my intentions are, both because I don't want to give myself credit for writing I haven't published yet, and because I think that doing so would somewhat spoil the act of interpretation from the standpoint of the reader. I can only offer you assurance in my belief that this is a necessary step toward the resolution of at least one thread in the story's tangled web of metaphors.