While relaxing on Gourmet Island, Toriko and Komatsu happen upon a dung-shaped Devil fruit, and ponder what it could taste like. Overhearing their conversation, Monkey D. Luffy informs them that the Devil’s fruit tastes horrifically awful, but Komatsu is sure that with the correct preparation, it will be truly delicious. So, while Komatsu begins to prepare a feast, Luffy and Toriko begin to gather ingredients, and decide to challenge each other to a contest to see which one of them can find the most food.
Not every manga can mash-up as seamlessly as these two did. Gourmet Island--could believably exist in the Grand Line of One Piece and also would make sense in the Toriko universe (though of course it wouldn't exist in both, since they have contradictory world maps). Devil Fruit--obviously originates in One Piece, but works well as a "specially prepared ingredient," a concept important in Toriko. Luffy and Toriko also share a love for eating food and defeating strong monsters to consume their meat. And the idea of banquets is used in both manga as well as a way to wrap up storylines, so it feels right at home. The art styles are a bit different, but they go together alright (though I didn't really care for the named monsters). I also didn't care for Komatsu's apparent idolization of Sanji or the way they chose to summarize the main plot goals of the respective mangas at the end there. It's biggest flaw is that it's not doing anything exciting (I don't consider cross-overs inherently exciting). It found a good way to mash the two universes together, but it's not as though that's exciting or even interesting beyond the conceptual appreciation of the difficulty of a clean mash-up. But it's okay.