I had this dream when I was maybe 7 or 8 years old.

It’s late at night, and I’m in my bed on my left side, my eyes shut. Beside me is my mom, asleep, on her left side with her back to me. I hear a clicking and chattering — something is near us, next to the bed. I opened my eyes just for a moment, enough to see my mom sleeping there and a faint white light in front of her, a white halo coming from whatever’s clicking and whirring. I keep my eyes closed and try to wake her up by shoving her, but she stays asleep.
I reach my arm past her sleeping form to see if I can get the thing to go away. I reach, not knowing what I’ll end up touching; I grasp something cold, metal, like a framework, like something built from Meccano pieces. My fingers move between the spaces in its “head,” or what I assume is its head, as though I’m gripping a cage. I can feel small moving parts like gears and wires. Mustering a little courage, I shake the head as violently as I can, to make it leave; the head moves as though gimballed on a long mechanical neck, bobbing and not really resisting my shaking it, just enough to stay up straight. It is much like an animatronic brachiosaur head, without the rubber skin. Having failed to scare it away, I pull my hand back and hide behind my mom as best I can.