The Fart in a Balloon is an accessory that combines the effects of the Fart in a Jar and the Shiny Red Balloon. It boosts jump height by 33% and jump speed by 30%, increasing the player's first jump's height to ~10.5 blocks (~75% increase), and provides a double jump that goes to 18.5 blocks, for a total of 29 blocks. Unlike most other double-jump balloons, the Fart in a Balloon's full jump is high enough for the player to take minor fall damage, unless the player has fall damage immunity accessories like the Lucky Horseshoe. The jump also makes a fart sound.
The Fart in a Balloon can stack with separate double-jump items, such as the Tsunami in a Bottle and the Cloud in a Bottle. Stacking multiple items that give the same type of double-jump (in this case, Fart) will not increase the effects of the jump.