The Snag Machine is an object originally created by Team Snagem, then recreated by Prof. Krane. It is used to steal Pokémon from their owners during battle, by throwing out a Pokéball that can't be blocked.
The main protagonist of Pokémon XD: Gale of Darkness was given the Snag Machine by Prof. Krane and his lab team. They told him to use it after Cipher had come back, to catch their and help with the process of purification. This version had a Shadow Reader attached that allowed the user to see the dark auras around Shadow Pokémon.
The Snag Machine is worn on the user's arm, and it has a large bulge sticking out where the shoulder should be. It attaches to the hand. A cable of sorts is used to connect the Snag Machine with the Shadow Reader. The Shadow Reader has a Pokéball symbol on the lens. All of the Snag Machine has a silverish color to it, including the Pokéball Symbol on the lens.
The Snag Machine's original use was to still Pokémon from innocent people. After the protagonists obtained it, they used it to take Shadow Pokémon in order to purify them. The female protagonist in Pokémon Colosseum would yell at the male protagonist if he tried to use it on a normal Pokémon.
Before it was obtained by the protagonists, Team Snagem used it to steal Pokémon for Cipher to close their hearts. Team Snagem wanted power, so they created the Snag Machine in order for them to reach this goal.
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