In a fanfiction, Shadow could lose his memory and end up in the My Little Pony world. The ponies take him in and help him regain his memories. Along the way, he forms bonds with different ponies. For example, he might befriend Twilight Sparkle who is interested in his unique abilities and tries to use her magic to help him. As he slowly remembers who he is, he has to decide whether to stay in this new world of friendship or return to his own world.
One idea could be that Shadow somehow gets transported to the My Little Pony world. He might initially be a bit of an outcast due to his different and edgier personality compared to the ponies. But as the story progresses, he could learn about friendship and harmony from them and in turn, teach them about his own values like loyalty and justice in a different sense.
A more complex idea could be that there's an alternate universe where the villains from both worlds combine forces. The Green Goblin teams up with Discord. In this fanfiction, Spiderman and the Mane 6 have to put aside their differences in fighting styles and cultures to defeat this powerful alliance. They learn from each other's strengths, with the ponies teaching Spiderman about the magic of friendship and Spiderman showing them some cool combat moves.
One idea could be that the Omnitrix somehow gets mixed up with the magic of the sirens. Ben, as one of his alien forms, has to deal with the alluring powers of the sirens in the My Little Pony world. Maybe he has to stop them from using their voices to take over Equestria while also not getting charmed by them himself.
One interesting crossover could be Sonic's speed being used to help the ponies in Equestria in a time of crisis. Maybe he races to deliver an important message across the land faster than any pony could.
They can co - exist if there is a common goal. For example, if a powerful and evil force threatens both Shadow's world and the My Little Pony world. They would have to work together to defeat this enemy. Shadow could use his combat skills and speed, while the ponies use their magic and friendship power.
One idea could be a story where Sonic accidentally runs into the My Little Pony world. He could team up with Twilight Sparkle to stop an evil force that's threatening both their worlds. Maybe a chaos - causing villain has found a way to cross between the two realms.
A more complex idea could be that an enemy from the Ben 10 universe teams up with a villain from the My Little Pony world. Ben and the Mane Six then have to combine their skills and powers. Ben uses his various alien forms to fight physically, while the ponies use their magic and friendship to combat the evil forces on an emotional and magical level.
Some fanfictions in 'my little pony bloopers fanfiction' might explore the ponies' reactions when they get their magic powers mixed up. This could lead to some really funny and unexpected situations, like Twilight Sparkle accidentally making it rain cupcakes instead of controlling the weather properly.
One idea could be a story where the prince has to go on a quest to save his kingdom from a dark magic that is slowly consuming it. He could meet the My Little Pony characters along the way and they help him with their unique abilities.
One interesting idea could be how the pony personalities translate to human characteristics. For example, Twilight Sparkle might be a super studious and intelligent girl. Another could be the relationships, like how Rainbow Dash's competitive spirit might play out in human high school sports.
Some fanfictions might explore the idea of pony wrestling tournaments. These could be grand events with different levels of competition. There could be underdog ponies who rise to the top through their determination and skill. And the fanfiction could also focus on the crowd reactions, the excitement in the stadium, and how the ponies' friends and families support them during these wrestling events.