The Ripple of Time is a portal generated by Celebi in order to travel across timestreams. It plays a pivotal role in Zoroark: Master of Illusions.
Overview
The Ripple of Time resembles a green portal, in which there are illuminated shards of green crystals seemingly floating in mid-air. When an individual named Grings Kodai came to Crown City 20 years prior to the start of the storyline, he absorbed the energy of the Ripple of Time, thus enabling him to see visions of the future. As a side-effect of this, all of the plant life within Crown City withered and died.
The Ripple of Time's primary purpose is to allow Celebi to travel through time, but it requires a tremendous amount of energy to do so. This energy is shown to be able to be harnessed by a single human, which can grant them the inane power to see visions of the future.
Kodai experiencing a Ripple Vision.
The Ripple of Time, once drawn into a human body, can often produce induced visions of their future. This allowed Grings Kodai to bear witness to the arrival of Ash and his friends, as well as to determine the new location of the Ripple of Time within Crown City. When a person imbued with the energy of the Ripple experiences said vision, their eyes become tinted green and they are unable to move for the duration of the vision.
Over time, the energy from the Ripple of Time disperses, and the visions become less frequent and prolonged. The Ripple of Time is ordinarily invisible to the naked eye, but through the use of Foresight it can become visible. Kodai also has a mechanical extension which can channel the Ripple of Time's energy into his body.