Splinter discovers that the Retro Mutagen Ray Generator is actually just a hologram. Once again the Sensei has been duped by Shredder, who tells him if he wants the Retro Mutagen Ray that he must first taste his blades, and once again Shredder engages him in marital arts combat. Krang feels ill-prepared to handle the "boys in green" by himself, so he summons Shredder. With the flip of a switch, Shredder imprisons Splinter in an electric cage and disappears to save Krang. Fearing that Shredder will use the Retro Mutagen Ray Generator on the Turtles in his effort to save Krang, Splinter uses one of his long fingernails to remove a metal screw in the floor, heaves it through the electrical cage and destroys its generator.