Any original Pokémon fan knows of the researcher, Bill, and his weird tendency to accidentally turn himself into a Pokémon -- that or getting himself stuck in a Pokémon costume. For fans who grew up during Generation 1 of the franchise, the most memorable example of this in the anime is when he's stuck in a Kabuto costume, and in the first video games when the same issue strikes again.
As it turns out, those aren't the only two times the eccentric researcher has had to deal with such problems...
Pokémon Transformations
Bill has actually transformed into a Pokémon quite a few times. In the Zensho Pokémon manga, for instance, he accidentally gets fused with his Nidoran, then gets caught by Satoshi while checking his email. Once Satoshi finds out what happened, he helps separate Bill from Nidoran and, as a sign of gratitude, Bill lets him add the Eevee family's data from his computer to his Pokédex. He also gives him an S.S Anne ticket, just like in the game.
In the Pokémon Adventures manga, he becomes a Rattata after -- wait for it -- his shirt gets caught in the doorknob of a pod in his lab. The door accidentally closed and Bill's broken system activated on him and on a Rattata in the other pod, causing the transformation. Thankfully, Bill gets turned back by Red, following which he authorizes the latter to use his storage system.
In Pokémon Red and Blue, a similar screw-up occurs that leads to another transformation. The player is the one who helps him get back to normal, after which he will offer the S.S Anne ticket and let the player use his storage system. Bill might be a scientific genius, but he sure is a klutz.
Costume Screw-Ups
Despite being well-known to fans, Bill only makes only one appearance in the Pokémon anime. He shows up in Episode 13, "Mystery at the Lighthouse," of the Pokémon Indigo League arc. In the anime, he's stuck in a giant Kabuto costume when he's encountered by Ash, Misty and Brock. He tells them he's a Pokemon researcher studying a mysterious giant Pokémon, which he's been trying to communicate with. Although the Pokémon's identity has never officially been revealed, its silhouette makes it look like a giant Dragonite -- perhaps a Dynamax form before its time.
It's also worth noting that Bill's wife has also been transformed into a Pokémon. And not just any old Ratatta or Nidoran. The poor woman morphed into the Mythic Pokémon Mew in the Pokémon Pocket Monsters manga following yet another failed Pokémon experiment. She later steals a Moon Stone in order to try to get back to normal. Bill, who'd been transformed into a leopard (yes, an actual animal) following a similar failed experiment, prevented Green from catching her and helped them both return to normal using the combined power of the Moon Stone and one of his machines. Bill's wife gets captured later on in the manga by Giovanni and his twin brother, who both seek to clone Mew's DNA in order to finish creating Mewtwo.
All in all, it would seem as if Bill has continuously, across every Pokémon medium, run into a severe dose of bad luck when it came to his machines (and costumes) malfunctioning. It's undeniable, however, that Bill's ongoing misfortune of constantly being turned into the objects of his research has made him one of the franchise's most easily recognizable and memorable characters. Bill has even made a reappearance in the Pokémon Let's Go Eevee and Pikachu games, where he once again got turned into a Pokémon, except this time, he transformed into a Nidorino. A step up at least, right? Seems like poor Bill just can't catch a break.