The Kon Kon no Mi is a Paramecia-based Devil Fruit of great power. It allows the user to manipulate the emotion of Malice, and allows the user to create a physical representation of the emotion in the form of Tendrils. Consumption of the fruit turns the user into a Malice Human (悪気人間, Warugi Ningen). This fruit was forcefully fed to a young ???.
The tendrils manifested by the fruit are tendrils which embody the intent of malice, and allows the user to consume and command others under the influence of hatred. This command of complete hatred allows for these tendrils to also release blasts of pure evil intent, and provides access to a multitude of techniques, even some which allow for devastation of entire countries.
The Three Hearts (三心臓, San Shinzō) are additional organs which manifest in the consumer of the fruit. These hearts provide a form of immortality and for the consumer to not feel pain. The only known way to cause the consumer of this fruit pain is by striking all four hearts residing within their body.
The Malice can be manifested in a multitude of forms, the most common being tendrils. However, Michael is able to manifest Malice in a variety of forms, the main alternative being in the form of Black Flames. These flames are inextinguishable, and consume life itself.