How about Groudon, like a cave explorer to search the gems, stones and many mystery in different caves and mountains.

I'm not so much looking for characters specifically, more or less certain scenarios to do with a character becoming big. Though, that said, i'm not opposed to the idea of gems and other artifacts coming into play.

Oh ok, I just change another. Teenager Zekrom as he calls Zach, he always want growing up become stronger and bigger than others because he is different as just like normal same as others. A day, he just go out as alone, then he saw a Dusknoir as strange pokemon tell him a way to grow up become strong and big immediately. He want to get strong but the price is Dusknoir will take Zach into place never can came back his own home. He doesn't care about it and Dusknoir grinned and take him to the destination. He took by Dusknoir into that place and Dusknoir has disappeared. Just used telepathy and told Zach, he will in this place become stronger and bigger than other even the pokemon stronger than him. Many pokemon have come out, he thought is like arena for training but is wrong. Is just a few pokemon is very fat but is just shape like pokemons are slimes. Those slimes are feed the pokemons who have same wish for become stronger and make they just keep to eat. Some of pokemon have came before Zach have already became slimes for served the new pokemon. They will served the one who want become stronger and never satisfied pokemon

Sorry about pokemons became slimes, if don't want just said about all the slimes like pokemon shape. Those slimes taste like delicious foods.

I think is like that, sorry about my bad language and long scenario

hmmm, maybe someone trying to use a spell but it backfires either due to inexperience or it being difficult to perform, causing them to grow out of control, threatening to cause them to burst unless the spell ends on its own beforehand or someone else cancelling out the spell (without making it even worse, more than likely doing so at first)

I can see that being a potential event that happens, i'll give it some thought, thanks for the idea.

Hmm ... a nest lined with HP wings?

Sorry is me again, how about like a ghost who curse someone and making become bigger and bigger. As the ghost making change its size and body when until end of the process .

Thats an interesting idea, I like it, I'll see what I can do~