Pokémon Colosseum

Spoiler warning: this article may contain major plot or ending details.

The game starts with an opening scene depicting the player stealing equipment from the strongly guarded headquarters of Team Snagem, and then proceeding to flee with an Espeon and Umbreon as the base explodes. After riding on a strange one-wheeled motorcycle for a while, the player stops at the dilapidated gas station of Outskirt Stand. The player battles Rider Willie, who tells the player about Phenac City after he is defeated.

Upon reaching the new location, a pair of shady people are just leaving the city with a noisy, wriggling sack in tow. Once they see that they've been caught, one of the goons, Folly, starts a battle with the player. After defeat, both people get away, leaving the sack unattended. A girl emerges from the bag after some trouble undoing the knot, and claim to have seen the kidnappers use some kind of strange looking Pokémon. The girl becomes the player's partner and both go to find the Mayor to clear things up. A strange man bumps into the player as he leaves the Mayor's office, predicting that he will see the player again sometime in the future. The player and partner then enter the house as the girl proceeds to alert the Mayor of weird Pokémon that have a dark aura and attack humans. The Mayor assures the team that he will look into this case, and suggests going to the city's Stadium. At the doorway of the Stadium, some Snagem members recognize the player as the traitor who blew up their base. A battle with one of them ensues, and upon defeat, the girl tells the player that she doesn't care about the past, but she does encourage buying some Poké Balls for future use. After this scene, the girl, Rui, becomes the player's permanent partner, and will follow the player throughout the length of the game.

Then, after purchasing some Poké Balls at Outskirt Stand, the player returns to Phenac City, only to find it taken over by some thugs. The player tries to rescue the Mayor, but finding the decked-out Miror B. and his mischievous friends in his wake. The player's partner identifies the first Shadow Pokémon available for capture after entering a battle with Miror B.'s underlings, Folly and Trudly. After beating both in a battle, and/or capturing the Shadow Pokémon, the player tries to leave the city for Pyrite Town, but is waylaid by brightly clad goons at each exit. Each has a Shadow Pokémon, but defeat of one will cue the others to leave.

From this point, the player and partner will journey all across the Orre region, battling Trainers, snagging Shadow Pokémon, and uncovering the disastrous plan of the secret organization, Cipher. This shady group and its ambitious admins are the creators of Shadow Pokémon, closing their hearts to strengthen their stats. The player eventually learns how to reverse the effects of this process, and must capture all of Cipher's Shadow Pokémon to thwart the evil mastermind behind it all. After defeating Miror B in Pyrite Cave, Dakim in Mt. Battle, Venus in The Under and Ein in the Shadow Pokémon Laboratory, the player goes to Realgam Tower; after defeating the Admins again, Gonzap comes out and reveals that Cipher gave Team Snagem the Snag Machines; and that Snagem gave the Pokémon to Cipher, who created Shadow Pokémon; meaning that this was all one master plan hatched by Cipher. After defeating Snagem, Nascour—the boss of Cipher—is defeated by the player. Afterwards, it is revealed that Phenac City's mayor Es Cade is actually Evice, the true boss of Cipher. After he is defeated, he tries to escape; however, fortunately, a Ho-Oh uses Sacred Fire to stop him, saving the day.

Even with the true leader of Cipher under arrest, there is still a post-ending to be completed. Secc, from the Kids Grid, emails the player information about some interesting characters who end up telling the player about some points of interest. Eventually, the Snagem Hideout becomes available for exploration, the Shadow Pokémon Laboratory gets some Cipher refugees to battle, and a hidden Stadium in the Under is brought to the player's attention. Lastly, after all the Shadow Pokémon are snagged, the player will be notified of a Trainer that is attacking people with another Shadow Pokémon, who supposedly looks just like the player. After the copy's defeat, there are still Colosseum battles to be won and a Ho-Oh to be obtained in Battle Mode.

Story Mode: Gotta Save 'em All!
In the new Orre region, a sinister organization is capturing Pokémon and misusing them. It's up to you to restore balance. Seek out all the Shadow Pokémon, snag them, and restore their spirit.

Unleash your Pokémon from Story Mode or send in your team from Pokémon Ruby or Pokémon Sapphire! Let them show off their true power in Single, Double, and Multi Battles!
Battle Mode: Worlds Collide!

The other half of the game, known as Battle Mode, consists of Colosseum Battle and Battle Now. This mode allows players to focus solely on Pokémon Battles, similar to the Stadium series.

While competing in the Mt. Battle 100 Trainer challenge in either the RPG or the Colosseum section of the game, players can receive Poké Coupons which can be used to buy items. Additionally, players have the option of storing Poké Coupons on a Pokémon Ruby or Sapphire game pak for later use. Below is a list of what players can receive after collecting a set amount of Poké Coupons.

Poké Coupon shop
TM29 (Psychic) 3500PC	TM13 (Ice Beam) 4000PC
TM24 (Thunderbolt) 4000PC	TM35 (Flamethrower) 4000PC
TM32 (Double Team) 4000PC	Ganlon Berry 15000PC
Salac Berry 15000PC	Petaya Berry 15000PC
Apicot Berry 15000PC	Leftovers 10000PC
Mental Herb 8000PC	Focus Band 10000PC
White Herb 8000PC	Quick Claw 10000PC
BrightPowder 10000PC	King's Rock 10000PC
Scope Lens 10000PC	Choice Band 10000PC

Pokémon Colosseum is compatible with all five of the core series Pokémon games on the Game Boy Advance. Items and Pokémon can be traded between them in the same manner that they can be traded between each other. However, the player must have defeated Evice in the main story mode in order to unlock it, have a GameCube-Game Boy Advance cable, and a Game Boy Advance.

Main article: Pokémon Colosseum beta

Main article: Staff of Pokémon Colosseum

• Despite being on the cover, Groudon and Kyogre are not available in the game unless traded from a Game Boy Advance game.
• The starter Pokémon, Espeon and Umbreon, already have some experience points toward the next level at the start of the game.
• The game erroneously calls Frenzy Plant "Solid Plant".
• If a Pokémon is traded from Pokémon XD to a GBA game and then to this game, the caught location will most likely be displayed as Mt. Battle, regardless of where it was actually caught in Orre, even if it was caught in an area accessible in the game, because both games use exactly the same internal index list for locations. Doing the reverse also produces a status screen oddity.
• Unlike the Pokémon Stadium series, Pokémon in this game retain their computerized voices, identical to those in the GBA games.
• In Pokémon XD: Gale of Darkness, the Trainer in zone 93 of Mt. Battle has Espeon, Umbreon, Raikou, Entei, and Suicune, Colosseum's starter Pokémon and Shadow legendary Pokémon.
• Pokémon Colosseum and Pokémon XD: Gale of Darkness are the only RPG Pokémon games released after Pokémon Crystal not to give the player the choice of playing as either a boy or a girl.
• None of the Pokémon obtainable in the game are from Generation I.
• In Europe, a GameCube Bundle could be purchased which included Pokémon Colosseum, a memory card, Pokémon Box Ruby & Sapphire as a bonus disc, and a GameCube-Game Boy Advance Game Link Cable.
• A trailer for Pokémon Colosseum was included on the bonus disc that came with preorders for Mario Kart: Double Dash!!. The trailer shows an early, more simplistic logo for the game, followed by various story and battle footage with Japanese text.

• Official PDF-file manual for Pokémon Colosseum (English)

• Staff of Pokémon Colosseum
• Pokémon Colosseum Snatcher Leo - manga adaptation
• Pokémon Colosseum Snatchers - manga adaptation