Wall animal

There is a nocturnal animal living inside/right outside my wall that seems furiously intent on gnawing it's way inside, judging from the maddening sounds it makes at night. It's been gnawing in that wall since last summer, was gone (hibernating?) through the winter, and has last night started up again where it left off. I desperately hope it most absolutely does not succeed in one day gnawing its way clear through the wall and onto my bed.