Black Kabuto is a smaller, dark version of the original Kabuto.
It was developed by Usopp during the two year timeskip. It is first clearly seen and named when Usopp fights against the guards of Ryugu Palace. Besides being more easily portable compared to the previous Kabuto (just slightly larger than his old slingshot, the Ginga Pachinko, in its default state), it retains the same design and functions, at least in its standard form. He uses it primarily in conjunction with his Pop Greens and other new attacks, but is also capable of using attacks from his old arsenal.
The Black Kabuto can turn into a stronger form called Grow Up Black Kabuto upon contact with water due to a Chomping Grass living inside Black Kabuto. In this form, the slingshot extends and the actual sling, while getting bigger, also takes on the appearance of the aforementioned carnivorous plant life form, allowing it to consume large amounts of rubble around it. In the process, it grows to a large size and can use the rubble as ammunition to attack its opponents.
Main Article: Pop Green
After two years of training with Heracles, Usopp has gained mastery of a new type of powerful weapon: the Pop Green. They are seeds of hostile plants that can grow at incredible speed. According to Heracles, these seeds have various uses, especially in combat. Usopp uses these seeds as ammunition for his new slingshot. However, not all these Pop Greens are used for battle purposes, and some can be used for utility functions.
- Green Star: Devil: Shooting a Pop Green, Usopp creates a large Venus Flytrap which attacks his enemies. In addition to being able to eat enemies with its large mouth, it can ensnare those nearby with its vines.