has to be a girl at some point u can see black footprint exiting the womens restroom

A dead viking.
Its the same stuff as the Draugr from Skyrim if you played that, just norse revenants who are pissed if you disturb their grave and have supernatural powers.
I imagine it wasn't happy about the researchers intruding in its barrow

Yeah, i saw a book about Norse Mythology in a room near the animal shack (with a cut hand that holds a card). So it kinda makes sense if it's really a viking.