Foo Fighters allows bundles of plankton to exist in a humanoid form. It adopts a personality, along with the nickname F.F.; siding with the allies of the story.
Foo Fighters takes two main appearances. Naked, it is a tall, dark, robotic humanoid of masculine proportions, and an alien visage.
Later, it maintains the appearance of the dead prisoner Atroe; a woman of average height and slim build.
As F.F.'s identity develops due to her experiences with Jolyne the true form of her Stand takes on a more human appearance starting to resemble the body she took over while still retaining some of the features of its older form.
- Main article: Foo Fighters
Technically, Foo Fighters has two forms: one where it is in a body and one where it is not.
- Noncorporeal Form: While not in a body, Foo Fighters has the ability to traverse bodies of water at superspeed, spreading her plankton to faraway areas to manipulate whatever she chooses. She can also produce sub-bodies from plankton allowing her to effectively fight multiple opponents.
- Corporeal Form: In a body, she retains the ability to produce sub-bodies from plankton by forming a pistol on her forefinger, shooting parts of herself at her enemies like bullets. As the bullets are a part of F.F., she can expand and contort it at any time, somewhat similar to Sex Pistols. The downside is that she has to be constantly hydrated and can't fight for extended periods of time. As long as there is water, Foo Fighters can continue to multiply and travel.
- Water Control: She can control water by filling it with plankton. She is capable of creating a mirror out of one third of a cup of water.
- Healing: F.F. can heal people by sewing wounds quickly together on a microscopical level and filling them with plankton, preventing infection and blood loss, until they naturally heal. She can heal some of the most fatal wounds in a matter of seconds.
- Araki tried to draw something insectoid or reptilian. He thinks it looks more like a chameleon, a mutant, or a space alien than a microscopic organism.