The Fart in a Jar is an accessory that the player can equip, allowing them to double jump. Unlike the Cloud in a Bottle, the second jump will allow some propulsion if the jump button is kept pressed, behaving more like the Rocket Boots. Also, while wearing Hermes Boots or any of its derivatives, the second jump will activate sprinting.
- The Whoopie Cushion sound effect can be heard while jumping with this accessory equipped.
- The Fart in a Jar is the only propulsion item out of the Sandstorm, Blizzard, Cloud, Tsunami and itself that has 'in a Jar' at the end instead of 'in a Bottle'.
- The Fart in a Jar has the same jump height as the Sandstorm in a Bottle, but cannot be used to make a Bundle of Balloons.
- The Fart in a Jar and Fart in a Balloon don't make the fart sound effect.