From Bulbapedia, the community-driven Pokémon encyclopedia.
Pokémon Colosseum Snatcher Leo (Japanese:ポケモンコロシアム スナッチャーレオ), is a manga adaptation of Pokémon Colosseum's plot, starring Wes (Leo) and Rui fighting against Cipher. It is created by Oouchi Suigun, also known for the manga adaptation of Jirachi: Wish Maker.
Very little is known about it in the English-speaking fandom. The main reason for its rarity is that it was never collected in a tankōbon format. It was collected in three CoroCoro volumes, ranging from January to March.