I was editing TVTropes' BioShock page, and realized the BioShock 2 section could use a trope. However, I couldn't think of what such a trope would be named, and trying to find it with searches and lists hasn't seemed to help. I was hoping one of you could help me find the appropriate trope. Here's the situation:
Near the end of BioShock 2, as the player nears a hallway, a ball rolls down the hallway and into your view. The whole section is accompanied by eery noises such as children, but the game explains that as ADAM memory. What bothers me is that the ball rolling is never explained, referenced later or before (as explanation), or given any reason to be possible without an actual cause.
It sounds like something there would be a trope of. Any ideas what it'd fit into?