The Fart in a Jar is an accessory that allows the player to perform a double jump, accompanied by a farting sound effect. The fart jump will continue to propel you upwards if the ↷ Jump button is held, reaching up to 10.5 blocks on its own, or 16.5 blocks when put together with the first jump. Due to this behavior, the jump behaves more similarly to the Rocket Boots than the Cloud in a Bottle. Unlike the Rocket Boots, however, the jump cannot be used in multiple bursts, and cancelling the jump will forfeit the rest of the height.
With the Shiny Red Balloon equipped, total jump height increases to 29 blocks (10½ blocks + 18½ blocks). Jumping to that height can result in some minor fall damage if landing at the same height that was jumped from.
The Fart in a Jar is the only double-jump base accessory that has "in a Jar" at the end instead of "in a Bottle", and is the only double-jump base accessory that must be crafted.
During the Great Plague of London in 1665, doctors suggested that patients store their farts in jars to combat bubonic plague. Doctors believed inhaling the fumes would ward off the bad vapors that came with the disease.
The total height achieved with the Fart in a Jar versus the total height achieved with the Fart in a Balloon, including when submerged in water.