Snag Ball
A Snag Ball is a type of modified Poké Ball seen in both Pokémon Colosseum and Pokémon XD: Gale of Darkness. It is created by using a Snag Machine, and it is the only type of Poké Ball which can Snag an already caught Pokémon in the games.
It was initally developed by Cipher so Team Snagem could steal Pokémon from their trainers and give them to Cipher, who would change them into Shadow Pokémon. However, in both Pokémon Colosseum and Pokémon XD: Gale of Darkness, they are used by the main characters for the opposite purpose: to steal back the Shadow Pokémon from Cipher and purify them into normal Pokémon. In Pokémon Colosseum, they are the only type of Poké Ball the main character uses, since there are no wild Pokémon to be found in Orre. In Pokémon XD: Gale of Darkess, PokéSpots are introduced and normal Poké Balls can be used, but snagging Shadow Pokémon with Snag Balls is still the primary method of catching Pokémon.
When thrown, a Snag Ball is only visually different from a normal Poké Ball by five streaks of white which appear around it and close on the Pokémon being snagged as the Ball does. This effect looks like a hand grabbing the Pokémon. When a Pokémon has been caught with a Snag Ball, it does not say in the Pokémon's profile that it is contained in a Snag Ball. Instead, it says in the profile that its Ball is the type of Poké Ball which was initally converted into a Snag Ball. Presumably, this means that once the Pokémon is snagged, the Poké Ball reverts to a normal form.
In both Pokémon Colosseum and Pokémon XD: Gale of Darkness, there is a glitch whereby the player is able to make unlimited Master Balls using the Snag Machine. To make such Master Balls the player needs three objects: a Snag Machine, a Master Ball, and a Poké Ball of choice. First the player must send two Pokémon onto the field. Then for the first Pokémon's move choose the Master Ball and the Shadow Pokémon of choice. Then when choosing action for second Pokémon, press B to go back to the first Pokémon. This time choose the Poké Ball and the same Shadow Pokémon. For the second Pokémon choose any action. The snag ball will have the same functions as the Master Ball.