Ground Hog Day is the first episode in Bad Piggies. It has 36 levels plus 9 Cave levels.
King Pig, Ross, and Mechanic Pig notice a trio of Eggs faraway. The pigs open up a map to find their way to the eggs, only for it to be accidentally caught in a fan and torn to pieces. The Pigs must journey to recover all of the missing pieces of the map.
The episode gets its name from how the main theme of Ground Hog Day being based on land locomotion, hence the "Ground" in the title, and the Pigs as the focus, which is how "Hog" is part of the title and Groundhog Day, a holiday celebrated on February 2.