Pop Green

Pop Green (ポップグリーン) are the seeds of the hostile plants found in the forest of "Greenstone" on Boin Archipelago. It can grow from seeds to full-sized plants in moments.

History
Heracles uses these seeds as bullets, weapons, and tools. According to him, they have various uses, and he taught Usopp how they work.

Usage
Pop Greens are seeds with instant growth capabilities, being able to sprout into full grown plants in a matter of moments. Presumably native to the Greenstone forest in the Boin Archipelago, they have been effectively weponized by Heracles (who is shown to simply throw them) and Usopp (who fires them using Black Kabuto). How they are triggered is currently unknown, but different seeds are known to act on different stimuli.

Some grow upon impact, others grow in the prescence of an oncoming target, while another is capable of growing in mid-air. These seeds also have varying ranges and effects, even those not normally attributed to plants, such as one capable of piercing opponents, another being able to explode, while another is shown to release a shock wave. Each type of seed also has a different color scheme, which the user can use to tell what each one is capable of.

Usopp's Attacks
After two years of training with Heracles, Usopp gained mastery of the Pop Green as a new type of powerful weapon. According to Heracles, these seeds have various uses, especially in combat. It should be noted that the names given are not confirmed to be the plants actual name, rather the name Usopp has given to each attack.

Trivia

 * Pop Greens are similar in principle to Capsules from the Dragon Ball series.