Vicious is an Elite Officer of Team Rocket, but he attempted to take over Team Rocket with Celebi. In the English version, he's called Iron Masked Marauder.
He temporarily had Celebi in his clutches, but lost control of it after Ash and Sam helped it break the Dark Ball's hold over it. He tried again to capture Celebi without the use of his Dark Balls, but was defeated when Ash's Pikachu used Thunderbolt on his jetpack. He was captured and was most likely jailed at the end of the movie. His Pokémon were also seen released near the end, going back into the wild. In Team Rocket, Vicious is known as the Iron-Masked Marauder.
While interrogating an elderly Pokemon poacher, who had failed to capture Celebi 50 years ago, Vicious demonstrated the ability of his Dark Ball. Upon being freed by Scizor, Tyranitar appeared timid, but became evil upon being captured.
As part of his mission for Team Rocket, Vicious planned to capture Celebi. However, his task was impeded by Ash and the time-displace Sammy. However, he managed to trick Celebi into a trap, where he captured in it in a Dark Ball and turned it evil. Under Vicious' command, Celebi created a demonic-looking puppet from the woodland and began wreaking havoc. Luckily, Ash and Sammy managed to help Celebi remember the friendship between them, breaking the Dark Ball's spell.