Maybe the worm Pokemon crosses over into the world of the 'worm' (assuming it's from some other fictional or real - world context about worms). In this new world, it has to adapt and find a way back to its own Pokemon world. Along the way, it teams up with some local 'worm - like' creatures (not Pokemon) and they learn from each other's abilities. For example, the worm Pokemon might teach them about using elemental powers, and they might teach it about survival in their world.
One possible plot could be a trainer in the Pokemon world discovers a strange worm - like Pokemon that has abilities never seen before. This Pokemon could be a key to unlocking a hidden power within the region that an evil team is also after. The trainer has to protect the worm - like Pokemon and use its unique powers to defeat the bad guys.
A cool plot might involve a scientist in the 'Plague Inc' world who accidentally discovers a portal to the 'worm' universe. As a result, the diseases in 'Plague Inc' start to mutate by incorporating the traits of the worms. Meanwhile, the worms also start to spread like diseases in the 'Plague Inc' world. Characters from both sides would have to figure out how to stop this strange crossover phenomenon before it destroys both worlds.
One interesting plot could be that Ben, using his Omnitrix, accidentally lands in the Pokemon world. He teams up with Ash and Pikachu to stop an evil organization that is trying to use both Pokemon and alien technology. For example, they might be creating hybrid creatures using Pokemon DNA and alien powers. Ben's different alien forms could have unique interactions with the Pokemon. His Four Arms form could be really strong in Pokemon battles, while his XLR8 form could be used to quickly traverse the Pokemon world to reach different areas in time to stop the villains.
One possible plot could be that Sonic and his friends accidentally end up in the Pokemon world. They team up with some Pokemon trainers to stop an evil villain who is trying to use chaos emeralds and powerful Pokemon to take over both the Sonic universe and the Pokemon world. Sonic's speed could be used in Pokemon battles, like quickly dodging attacks or getting to strategic positions on the battlefield.
Maybe there's a villain in the Pokemon world who is using some kind of Pokemon - related power to cause chaos, similar to the villains in BNHA. The heroes from BNHA have to team up with local Pokemon trainers to stop this threat. They discover new Pokemon abilities that they can incorporate into their own fighting styles. For example, Todoroki could learn from ice - type Pokemon how to better control his ice powers.
One possible plot could be that Mario and Luigi are exploring a new world and accidentally stumble upon the Pokemon world. They team up with Ash and Pikachu to stop Bowser who has teamed up with Team Rocket to steal all the Pokeballs and use the Pokemon's power to take over both the Mushroom Kingdom and the Pokemon world.
A possible plot could involve a mad scientist who combines the DNA of a worm with some sort of mutagen that gives it super - human like intelligence and abilities. This new 'worm - creature' starts causing chaos in the city. Spiderman, being the friendly neighborhood hero, investigates. He discovers that the worm - creature is not entirely evil but just confused. So, he tries to help it while also protecting the city from its accidental destruction.
A young and curious Pokemon trainer would be a great main character. This trainer could be someone who is always on the lookout for rare and unique Pokemon. When they encounter the worm - like Pokemon, they are immediately intrigued and decide to make it a part of their team.
Well, perhaps a plot where a trainer is exploring a strange new area and somehow crosses into the Warrior Cats' world. The trainer's Pokemon have unique abilities that the Warrior Cats have never seen. For example, a Charizard could help the Warrior Cats during a forest fire by using its fire - breathing ability in a controlled way. In return, the Warrior Cats teach the Pokemon and the trainer about their way of life, like hunting and stealth. As they interact more, they learn to respect each other's differences and strengths.
One interesting plot could be that Naruto and his friends are transported to the Pokemon world. Naruto, with his determination and ninja skills, decides to become a Pokemon trainer. He might choose a Pikachu as his first Pokemon because of its spunk, similar to his own. Along the way, he discovers that some of the Pokemon have chakra-like abilities and he tries to use his ninja knowledge to train them in new ways. His friends also each choose their own Pokemon and they compete in Pokemon battles while also trying to find a way back to their own world.
Maybe in this crossover, some Pokemon are accidentally sent to Danny's world. Danny has to protect the Pokemon from being captured by the Guys in White while also trying to find a way to send them back. Meanwhile, a certain Pokemon, like Gengar, forms a special bond with Danny because of their shared ghostly nature.