Bionicle
Upon his defeat, Makuta released the ancient Bohrok. Bohrok are robotic drones that were designed to "cleanse" the island of Mata Nui to its state "in the before-time". The Bohrok began to tear through the villages on the island, forcing Matoran to flee. One inventive Matoran of Earth, Nuparu, builds a powerful vehicle called the Boxor, made from parts of a damaged Bohrok in order to fight off the swarms. The Toa, unaware of the Bohrok's purpose, collected the Bohrok's Krana (mask-like creatures that function as their brains) to confront the Bohrok Queens, the Bahrag: Cahdok and Gahdok. The defeated Cahdok and Gahdok are sealed in a prison created by the Toa's elemental powers. The Toa Mata are then exposed to a substance called Energized Protodermis, which transforms them, granting them new armor and weapons. They renamed themselves the "Toa Nuva".