This video shows you how to get the skull that is hidden in Bad Piggies Ground Hog Day Level 1-27. If you zoom out, you’ll see a skull on the ground below to the left, in front of the cave exit. Build a high contraption, and place the pig on top. Navigate slowly to the right. The pig should roll down the tunnel onto the skull below.
If you have a different strategy for completing this level feel free to leave a comment below.