Pokémon Colosseum is different than the mainline Pokémon games in a lot of ways. It was on a home console, for one thing, and in 3D at a time when most Pokémon games were still from a top-down 2D point of view. One of the strangest differences, and lies, that Pokémon Colosseum features, however, is that the player can't catch all of the legendary Pokémon featured on the cover of the game's box.
Developed by Genius Sonority and released on the Nintendo GameCube for North American audiences in 2004, Pokémon Colosseum takes place in a brand new region, called Orre. The player controls Wes, a former member of Team Snagam, as he works to rescue "shadow Pokémon," which are Pokémon that have had their hearts darkened and manipulated by Team Cipher. This mechanic is why Pokémon Colosseum is so different than other entries in the series - the player simply can't catch 'em all. The only Pokémon that Wes can add to his team need to be shadow Pokémon that he steals back from other trainers, so he can purify their heart.
The restriction on which Pokémon the player can or can't catch even extends to the game's legendaries. The box art for Pokémon Colosseum features Groudon, Kyogre, Entei, Suicune and Raikou, so which ones aren't available for the taking?
Box Legendary Pokémon Colosseum Players Can't Catch
Out of the five legendaries featured on the box art, Wes can only catch Entei, Suicune and Raikou. The trio of legendary beasts are spread throughout Orre, but in order to catch them, the player must take on powerful figures from within the Team Cipher administration. Strangely enough, however, this isn't the case with Groudon or Kyogre, who arguably take up more real estate on the cover than the three legendary Pokémon which are actually catchable.
When Pokémon Colosseum came out in 2004, it was the height of Hoenn and Generation 3, as Ruby and Sapphire had been released a year earlier in North America. Pokémon Emerald would launch a little over a year later, in May 2005. For some reason, because of this, Nintendo and the Pokémon Company put Groudon and Kyogre on the cover - likely to represent the current Pokémon generation on Game Boy, even though Wes couldn't catch them in the game itself.
However, this doesn't mean that Groudon and Kyogre weren't obtainable in Pokémon Colosseum. If the player so desires, it is possible to transfer the two legendaries to the game through Ruby, Sapphire or Emerald. Plus, to make it even weirder, there's a legendary Pokémon that Wes can catch in Pokémon Colosseum that's not on the cover at all - if the player purifies every shadow Pokémon, they can catch Ho-Oh at Mt. Battle, which is where Entei is originally found, and Jirachi was available as a pre-order bonus for enthusiastic fans.
To this day, Pokémon Colosseum remains the only game to feature an uncatchable legendary Pokémon on its front cover. Maybe Nintendo realized how confusing this was to players, or maybe the company decided it was easier to stick to one Pokémon on the cover per game, but either way, it's a strange phenomenon that hasn't been repeated since.