Only evil, "Shadow" Pokemon could be snagged, and only when they're purified outside of a fight would they behave like normal Pokemon.
POKÉMON XD GALE OF DARKNESS ROM EMUPARADISE PORTABLE
Instead, players had the unique ability to "snag" the Pokemon creatures away from the trainers during a fight, something that the portable adventures didn't offer. The twist, though, was that players didn't actually catch the critters in the wild like they did on the Game Boy system.
Last year's Pokemon Colosseum essentially extended the Pokemon Stadium multiplayer design with a unique single player adventure that slid in some of the familiar gameplay mechanics of a traditional Pokemon RPG. It's still an involved, extensive quest it's just a huge letdown for what's most likely the last Pokemon "hurrah" for GameCube owners. But the designers didn't do enough to distinguish the overall production from last year's game. Sure, there's a new character in the lead with his own unique experience in the world of Pokemon. Pokemon XD is so close in design to Pokemon Colosseum that it's hard to get excited for the idea of "Pokemon on the Big Screen" this time around. Pokemon XD: Gale of Darkness approaches the idea of a Pokemon sequel almost exactly the way developers do for the franchise on the handheld: build a "new" game using the existing parts created in the original design. But Pokemon Colosseum started bridging a path towards the successful RPG formula, offering that familiar "Gotta Catch 'em All" battle-based gameplay, all the while keeping a safe distance away so as not to step on the Game Boy versions' toes.
Pokemon Colosseum's release last year was a major event because it was the first example of the Pokemon RPG design on a system outside of the Game Boy platform - Pokemon console titles have always been strict spinoffs that purposely remained separate from the handheld adventures.