Launching "." with gravitons?

[Floorface]

It's not launching a period, rather what ever it hitting the window doesn't have a name. The message would normally be: "The steel-reinforced window is hit by [object].", but in this case the [object] is blank, and therefore it doesn't appear giving the message you see in your example.

Oh alright. Though its still strange that this blank object was suddenly created.