Rokakaka Fruit

Equivalent Exchange
The fruit of the Locacaca tree follows the same principles of "equivalent exchange" as the grounds of the Higashikata estate; they are capable of granting anyone who eats it "something" by taking "something else" from them. The most faithful example of this concept is when the old man uses the Locacaca fruit to regrow his lost leg in exchange for his eyesight, both of his eyes transforming into stone and breaking apart soon thereafter. Apparently this process can be repeated as long as someone has a fruit, continuously sacrificing random parts of their own bodies in order to gain back what they had given in the previous instance.

Yasuho's research into the fruit of the Locacaca shows that the equivalent exchange provided by the fruit takes the form of part of the afflicted's body turning to stone. Infertile women gave birth, but their breast milk turned into sand and the elderly grew back teeth made of stone in order to eat again. Dr. Wu Tomoki has performed research on the fruit and discovered that 125 grams of the fruit are needed to perform one unique equivalent exchange. Upon being ingested, the fruits begins being absorbed as early as in the labial frenum down to the small intestine, in time invading the whole body through the blood. Then the Locacaca takes 3 minutes and 21 seconds to heal a specific lesion in the body, prioritizing the gravest one over others, and taking the cells and nutrients from another region of the body which turns into rock. However, the chosen region is random and no one knows how it chooses. Until then, Wu has used the Locacaca in conjunction with Doctor Wu to prevent the Locacaca from entering vital areas like the brain and cancel the risk of death.

Urban Guerrilla mentions that while the process is beneficial for Rock Humans, there is some incompatibility between the plant and regular humans due to the carbon in a human's body cells and its differences with the qualities of silicon-compound organisms.

Miraculous curative powers
Perhaps the most intriguing and relevant ability of the fruit to the storyline is the effect it has on those afflicted with the stone sickness; namely the Higashikata family, the Joestar family and the dog Iwasuke. As shown in the case of the latter, Yotsuyu was able to 'cure' it of the stone sickness by feeding it a piece of a Locacaca fruit.

The abilities of the fruit and their correlation to the Rock Humans and stone sickness make them a constant source of interest to the antagonists of JoJolion, which motivates the conflict between them and the allies of the amnesiac Josuke.