Brain Storm

"It entered my skin and I can sense it climbing up my body. The insides of my body are being polluted and melted, causing these holes to become bigger and bigger."

- Rai Mamezuku

Brain Storm (ブレイン・ストーム) is the Stand of Urban Guerrilla, featured in JoJolion. It is a colony of small blocky Stands that can melt flesh when they sting someone.

Appearance
Brain Storm is a colony of pointed block-like creatures which resemble. It has spiked feelers that can extend to penetrate the surface of skin. The stand is also extremely small, much smaller than other colony stands.

Brain Storm is violet and dark purple in the colored manga.

Hemolysis
Brain Storm is a bacterial-like Stand that Urban Guerrilla sends out of his hands, which can melt the flesh of anyone touching it. First, they grab onto the surface of the skin with their feelers. They break through the skin and their feelers extend inside the victim's body. The Stand causes and enters deeper into the body, while also constantly multiplying exponentially. This causes the target's body to break down as if holes are being dug into it.

As Rai Mamezuku points out, once the Stand has made its way into the body it is impossible to remove, requiring immediate amputation to prevent death. However, the Stand is easily washed away with water if it has not entered the body yet.

Trivia

 * The holes that the Stand creates in its victim's body have the appearance of holes in glaciers.