The bad piggies in "Angry Birds" steal the eggs from the bird flock on Piggy Island. The King Pig orders them to commit the theft because he wants to eat something different from his usual meal. This causes the birds to get angry and launch themselves at the piggy strongholds.
There is a wide variety of bad piggies, including their king with a childish temper, bossy pigs, stubborn pigs, brainy pigs and clumsy minion pigs. Many different birds with a range of powers attack the piggy forts to stop the egg theft, including Terence that bulldozes anything, Matilda that drops egg bombs and the explosive Bomb bird.