Who's that knocking on my....skylight?

So last night, left alone with the cats, the buzzer on the dryer indicates it is done. Shortly after that I hear a frantic scratching. I dash to the dryer and fortunately find nothing out of place, and the scratching has stopped. I looked around the house, nothing. Then I hear it again. Eventually I find this.

We're in the middle of updating our bathroom. Step 1 is removing the wallpaper. Step 2, after looking for interesting patterns in the glue, is it's removal.

Step 2.5, it turns out, is repairing the damage from removing the wallpaper.