The Mystic Key is a weapon created by mystic warriors to banish the Krang into their prison dimension in Rise of the Teenage Mutant Ninja Turtles: The Movie.
Description[]
The Mystic Key is a small, dark grey cylindrical object with light grey, abstract, embossed patterns and a fractured and blemished surface. Both ends of the Key and its backside seemingly have symbols of unknown origins that glow pink when the Key is active. It has an extraordinarily durable composition, unable to even be damaged by efforts to destroy it. The Key is the doorway to the prison dimension of the Krang, created to eternally seal them within it.
History[]
The Key was created a millennium ago by four unnamed mystic warriors to seal the Krang away from Earth's dimension after they invaded and ravaged Japan in an effort to take over the entire planet. Although the Key's creators sought to forever conceal it to keep it out of malicious hands, eventually, it ended up in New York being advertised as a "super cursed" object as part of an artifacts exhibit.
In the original timeline, the Key was stolen from its exhibit and put into the possession of the Foot Clan who used it to free the Krang from their prison dimension atop Metro Tower. Their release allowed the Krang to create an apocalypse as they violently dominated the Earth, achieving world domination by 2044. Casey Jones II was sent backwards in time from 2044 to the day the Key was first stolen in 2020 in an attempt to prevent the Krang apocalypse with an illustration of the Key drawn by Leonardo to help Casey identify it. Warren Stone and Hypno-Potamus were called upon by the Foot to steal the Key from its exhibit, however, they were opposed by the Turtles. The Key flew from Warren's van into the air where Raphael used Hamato Ninpō to catch it, but Leonardo sabotaged his attempt to instead teleport the Key to himself. However, by the time Leo had drawn his portal, Raph had already grabbed the Key, resulting in Raph entering the portal. Leo quickly closed his portal to prevent Raph from striking him, severing Raph's energetic hand that held the Key from the rest of his construct, leaving the Key exposed for the Foot to easily collect for themselves. After obtaining it, Warren, Hypno, and the Foot teleported to their hideout to prepare the prison dimension-opening ceremony. Later that night, the ceremony was disrupted by Splinter, Casey, and the Mad Dogs' intrusion who were there to take the Key from the Foot. Before Casey could stop him, Foot Lieutenant used the Key to unseal the prison dimension and free the Krang. During Splinter, Casey, and the Mad Dogs' retreat from the battle against the Krang, Leo was able to seize the Key and stop Krang Three from expanding the dimensional doorway to unleash the Technodrome, bringing it to the lair. April O'Neil and Splinter resolved to destroy the Key to prevent the now-closed Krang prison dimension from being accessed, but their many attempts proved unsuccessful. They carried the Key with them inside April's backpack as they fled from Krang Two and her Krang zombies. Soon after they reunited with Casey, Donatello, Michelangelo, and Leo inside Metro Tower, the Key was taken by Raph who was under Krang control as a Krang zombie. Krang One then traveled to the top of Metro Tower and used the Key to reopen the prison dimension and bring the Technodrome to Earth. Later as the Technodrome was halfway through the portal, Casey traveled to the top of Metro Tower to take the Key to close the portal with Leo and Krang One inside the prison dimension per Leo's orders, halving the Technodrome. The Mystic Key presumably remains in Splinter, Casey, and the Mad Dogs' possession intact.