Balloons are objects used by the Bad Piggies in Angry Birds to hold pigs and objects in midair. Once destroyed, the supported object or pig will drop.
Only in Angry Birds Rio and the Angry Birds episode, Birdday Party, if the player cuts the rope or stick holding the balloon, it will fly away.
Strangely, the balloons in Angry Birds doesn't have any ropes to tie with the objects but it still can hold objects and pigs in midair.
Balloons first appeared in the Angry Birds episode Danger Above, then later in Seasons and Rio. After that, it appears in Angry Birds Under Pigstruction with different shapes.
In addition to appearing as objects in the game, balloons have been used by the Pigs to steal eggs in opening scenes or cutscenes.