Mushroom Stadium (Brain Drain)

The Mushroom Stadium is a mushball stadium in Brain Drain. Mario, Luigi, Princess Toadstool, Toad, and the Mushroom King end up at the stadium while following the trail of people who had their minds swapped by Iggy Koopa's Synapse Switcher. They find that some of the mushball teams' members had their minds swapped with each other's, causing them to be confused about which team they should be playing for. By the end of the story, the group discovers that Fungus Up cures the mind-swapping, and the group inserts it into the water supply, which eventually cures everyone in the Mushroom Kingdom.