Foo Fighters

Foo Fighters (F.F) is a fictional character from the Japanese manga JoJo's Bizarre Adventure. The character is portrayed as an ally of the protagonist in Part VI: Stone Ocean.

Birth
Enrico Pucci had a shack of Stand disks near prison grounds, a collection of different Stands that he had collected over the years while in prison. The area around the shack is generally untouched and desolate. Enrico needed a guardian for these disks, lest they fall into unwanted hands. He threw a random stand disc into the ocean, which hit plankton floating on the surface. Unexpectedly, F.F was born.

Stone Ocean (2011-2012)
F.F, or Foo Fighters, was told to stay there by Pucci and to kill anyone (other than him) should they come close. Having no other purpose, it did as it was told. When Jolyne Kujo and Hermes Costello approached the shack during an outdoor activity, F.F attacked but was soundly beaten by both of them. Parched and close to disintegrating, it lamented its meaningless life, but was spared by Jolyne, who gave it water, despite Hermes' protests. Fascinated by its savior, it showed Jolyne her father's missing stand disc in gratitude. Subsequently, F.F. inhabited the body of a dead inmate and followed both of them back to prison. Although she likes the other people she has met, she has the strongest affinity for Jolyne for giving her freedom.

Later, tricked by Pucci, F.F. leads its friends into an ambush and suffers a severe blow to its body, knocking its stand disc from its head. Dehydrated and nearing death, it was able to hear the dying Anasui's requrest. He gave it permission to possess his body to pluck Jotaro's memory disk from him, not caring what happened to him as long as Jolyne would be happy. F.F. did pluck Jotaro's memory disk from Anasui's body but refused to possess it. Its spirit (strangely taking on the form of Etro's body) heals Anasui's wounds and thanks Jolyne for being her friend, glad that they met. When Jolyne decided to retrieve the disk to revive her, F.F declines, saying that it wouldn't be the real her but another F.F., and disappears into the wind.

Trivia

 * The body that F.F. inhabits belonged to a girl named Etro, named after the fashion brand of the same name. The initials F.F. are a marketing trademark of the Fendi fashion brand, another reference to its name.
 * Due to her plankton inhabiting the body it is in, F.F can contort in impossible curves and even slip through barred fences unharmed.
 * When not close to a pipe or hose, she tries to keep a 32. oz cup near her at all times.
 * True to her word, F.F. was the only protagonist to not have a Steel Ball Run counterpart at the end of Part 6.
 * The origin of the name Foo Fighters actually derives from an American comic "Smokey Stover" which was a comic about a Fire Fighter. The comic commonly used the nonsense word "Foo." In World War II, UFO's that resembled balls of fire were labeled as "Foo Fighters" in reference to the word foo and fire fighter used in Smokey Stover. This UFO would later become the namesake of the rock band Foo Fighters, which is the musical reference of the character FF.
 * FF's affinity to water could be a reference to the fire fighter in the comic Smokey Stover, who mainly relies on water to extinguish flames.