Google roof rats. That's what you got, since it's moving (and nesting) at night.
Google roof rat prevention. Seal off every part of your house, they only need a 1/4 inch space to get in. Make sure your gutter spouts have the hardware cloth type insert (Home Depot or Lowes) so they can't crawl up and into your gutters and chews through your facia board.
Once they leave a trail (they piss and crap non stop as they go) they keep coming back.
Good luck, you're gonna need it.
