Among the many manga series that ran in the early days of the Pokémon franchise, some are weirder than others. They have covered a variety of genres, from juvenile gag comics to standard shounen adventures to comics about playing the Pokémon video games. And yes, Pokémon has even dipped its toes in the shoujo romance genre, which just might be the strangest entry of them all.
Starting its run in 1997, Yumi Tsukirino's Magical Pokémon Journey is one of the first Pokémon manga, although the focus is far more on the romance than the Pokémon. The series' protagonist a girl named Hazel with little interest in Pokémon. Unfortunately for her, the boy she has a crush on, Almond, is quite obsessed with Pokémon, to the exclusion of all else. The premise is simple enough, but the strangeness sets in quickly as Hazel is recruited to collect Pokémon by a strange old man called "Grandpa," despite there being no relation between the two.
Hazel's first interaction with Grandpa is to complain about a love potion she bought from him exploding, rather than getting Almond's attention. He gets her to agree to his Pokémon collection quest (with the goal of causing humans to evolve like Pokémon) by offering better love potions as a reward. Hazel turns out to be something of a Pokémon prodigy, making friends with a talking Clefairy (many, but not all, Pokémon can speak in this series), convincing a Tangela to let her see the body under its vines, and saving Almond from a Gengar by gushing over its cuteness. While Hazel develops an appreciation for Pokémon through Pikachu and her later friend Clefairy, Almond remains her primary interest.
Within the first volume alone a number of other incidents occur that, even in the Pokémon world, seem like they would be impossible. In one chapter, Hazel is saved from drowning by a Horsea, which uses some sort of magic to help her breathe underwater. To repay that kindness, Hazel helps Horsea find a necklace it lost, which was intended as a gift for a mermaid that Horsea was in love with! Although it's known that the concept of mermaids clearly exists in the Pokémon series, since characters like Misty and her sisters dress like them in the anime, there's never been any indication that mermaids might be real, outside of this manga. Incidentally, Misty, Ash, and other anime characters appear in bonus joke chapters occasionally.
While the main focus of the series is Hazel's relationship with Almond, relationships between Pokémon characters and even Pokémon/human(oid) relationships do take the spotlight from time to time. A character named Pistachio has a Bulbasaur and a Chikorita, both of which have a crush on him, although he's understandably more interested in Hazel. Relationships between two Pokémon include a pair of Eevees, whom Hazel helps to go on dates and to develop a relationship, and Arbok and Wigglytuff, the latter of whom lives in a mansion that seemingly belongs to the Pokémon.
Magical Pokémon Journey ran until 2003, although only the first seven volumes were released in the US. The series is light-hearted and comedic, with a silly art style that's unlike anything else in the franchise. It was popular enough in Japan to get a follow-up series, Pocket Monsters Chamo-Chamo ★ Pretty ♪, which is more centered on Pokémon and never had an official English translation. And although the English volumes can be difficult to acquire these days, it's strange and amusing enough to be worth a read for any hardcore Pokémon fans looking for more.