What are some interesting ideas for a Mario and Sonic crossover fanfic?

One idea could be a racing tournament where Mario and Sonic team up against some new, powerful villains. They have to combine their unique skills, like Mario's jumping and Sonic's speed, to overcome the challenges of the track which is filled with traps from both of their worlds.

Well, a cool plot for Mario Sonic crossover fanfiction might involve a new character that can travel between their worlds freely and is causing chaos. Mario and Sonic initially suspect each other but then realize they need to join forces. For example, this character could be stealing power - ups from Mario's world and Chaos Emeralds from Sonic's world to gain ultimate power. They would have to explore both worlds, facing their respective villains' minions along the way.

One idea could be that Mario and Sonic have to team up to save both their worlds from a new, powerful villain that is threatening to merge their dimensions in a chaotic way. For example, Bowser and Dr. Eggman could accidentally awaken an ancient evil while arguing over who is the better baddie.

One idea could be that Sonic and Mega Man have to team up to stop a new villain who has the power to control both the robotic and natural elements. This villain is creating chaos in both their worlds. Another idea is a race between Sonic and Mega Man's robotic companions, like Tails and Rush, to see who is faster at a series of challenges. A third idea could be that Sonic accidentally enters Mega Man's world and has to learn how to fight the robotic enemies there, with Mega Man as his guide.

One idea could be Sonic crossing over with another popular game like Mario. Sonic could find himself in the Mushroom Kingdom and have to team up with Mario to stop a new threat that combines the chaos emeralds and power - ups from both worlds. Maybe Bowser has teamed up with Dr. Eggman to create this chaos.

One interesting plot could be that an evil force is threatening all of their worlds simultaneously. Mario, Sonic, and Megaman have to team up. Mario uses his platforming skills to traverse tricky terrains, Sonic's speed helps them reach far - off places quickly, and Megaman's arsenal of weapons is used to fight enemies. For example, they could be in a world that combines the best elements of the Mushroom Kingdom, Sonic's zones, and Megaman's stages.

One idea could be that Sonic and Mario have to team up to save both their worlds from a new, powerful villain who has the ability to manipulate time. This would force them to use their unique speed and jumping abilities in new and creative ways.

One idea could be that Sonic accidentally enters Equestria where Rainbow Dash lives. They could then have a race to see who is faster in the new and unfamiliar terrain for Sonic. Rainbow Dash might be amazed by Sonic's speed and Sonic could be intrigued by Rainbow Dash's ability to fly while racing.

One idea could be that Sonic accidentally enters the world of Equestria Girls while chasing Dr. Eggman through a strange portal. He then teams up with the girls to stop Eggman from stealing the magic that powers their world. Another could be a race between Sonic and Rainbow Dash which gets interrupted by a common enemy.

One idea could be a crossover with the Legend of Zelda series. Link could be a special guest in the Mario Party world, bringing his unique items like the Master Sword and Hylian Shield. He might participate in mini - games that require his combat skills or puzzle - solving abilities.