It was an awkward moment when everyone found the stadium.
Mario and company chased the Koopa Troop there, while Sonic and the Freedom Fighters all chased Eggman's forces there. They all wanted to see what that power source they detected was... only to find out they had been chasing each other.
"...Well," Sonic said.
"Yeah..." Mario said. The two stared at each other awkwardly while Bowser and Dr. Eggman glared at one another.
"This is a colossal waste of time," Bowser said, turning to leave.
"I agree," Dr. Eggman grumped. "Move out. We're going home!"
"I don't know," Peach said, admiring the architecture of the stadium. "A little cleaning, some magic here and there, and it would make a great place for an Olympic stadium."
Mario blinked. "You serious?" he asked.
Sally frowned. "Wait, magic?"
Peach nodded, creating some sparkles. "Our kingdom is rife with magic. Maybe combining it with your world's technology, we can set up some great games." She turned to Bowser and Eggman, the latter still leaving, the former having stopped to listen. "You all are invited, of course, so long as you play fair."
"You have got to be kidding," Eggman said.
"...No, no, we've done this before," Bowser said.
"SERIOUSLY?!" Eggman asked, shocked.
Bowser nodded. "Yeah. Sometimes I go go-karting with these losers. Or play sports, or this giant magic board game thing..." he shrugged. "It's something to do between conquest attempts. And honestly," he added with a vicious grin, "its rather satisfying to beat them in fair combat."
Peach nodded. "Paranormal-level abilities would be suppressed, of course," she said. "To keep everything fair."
"No zipping around at the speed of sound for you if we take part," Tails said to Sonic, getting the idea.
Sonic snorted. "Don't know how happy I am about that..."
Eggman stroked his mustache, looking thoughtful. "...I suppose. I don't really have any new plans... Not to sure about this 'playing fair' nonsense. But I do like the idea of beating Sonic at something."
Mario turned to Sonic. "So how about it?" he said. "I'm-a gonna go for it, Mr..."
"Sonic the Hedgehog," Sonic said. After a moment's thought, he added, "And yeah, it does sound fun."
"I'm-a Mario," Mario said, shaking Sonic's head.
Relucantly, everyone else agreed to it as well.
And so it began. Six teams were made. Team Mushroom Kingdom. Team Freedom Fighters. Team Eggman Empire. Team Koopa Troop. Team Independent Nasties. Team Civilian Heroes. The latter two teams blended heroes and villains from both worlds. The contests would last three months, with the winning team being granted wishes from a wishing star. And to win? Why, you simply had to have the most gold medals...