Galaxy Colosseum

Diddy Kong faces a Spiked Topman in the Galaxy Colosseum.

Galaxy Colosseum (Galaxy Arena in Europe) was a battle stage that appeared in Mario Kart Wii during online tournaments. It was essentially a round platform situated in outer space, specifically a Super Mario Galaxy/Rainbow Road-themed setting. Three tournaments took place on the arena.

In the tournament which took place between 1 and 10 June 2008, players had to compete for the fastest time by knocking a total of four giant Spiked Topmen off of the arena's edge using only Triple Mushrooms. Players could knock them away with a Mushroom boost.

Also, in the 2nd June tournament of 15 to 25th June 2009, it was the same, except the outer rings of the arena broke off, and players had to send six Spiky Topmen off of the stage.

For the 3rd tournament of March 2010, the player had to do the same as the 2nd June tournament of 2009 but with an exception: some Topmen could run away, and for this tournament, the player could use any Kart, Bike, or control scheme. Again, six was the required number to win.

According to the map of the stage, the size of this stage differs in each boss battle.

Due to the ending of the Nintendo Wi-Fi Connection service, and with it the Competition Mode, it is impossible to play on this course without using cheat codes or porting the course into other battle tracks.