he first Muruchi was originally seen chasing after Ryo Sakuma at the beginning of the episode, until encountered and sealed underground by an Alien Mates, who would later adopt the boy. However, Alien Mates was tragically shot and killed by a police officer in an angry mob (who were trying to kill the boy too).

The death of Alien Mates caused the sealing of Muruchi to be undone, allowing the monster to resume its reign of terror. Believing that those people who were responsible for the innocent alien's murder, Hideki Go initially refused to transform into Ultraman Jack and let the villagers reap for their sins, but he eventually did under the persuasion of Captain Ryu Ibuki. From the moment the battle began, Jack held the upper hand against Muruchi, He easily dealt with the monster in hand-to-hand combat, eventually forcing Muruchi to the floor. Jack threw Muruchi into a burning oil refinery, leaving the monster howling in pain, then finished him off by firing his Spacium Beam into the wreckage, killing him instantly.