One Piece has been running for 20 years now, and it's still surprising that Eiichiro Oda has kept larger parts of the lore a mystery this long after the series started. A few arcs have revealed some of how the world works here and there, but the series is still keeping major parts of the lore a secret. Despite their proliferation in recent years, the Devil Fruits are still relatively unknown as each new chapter introduces more and more kinds.
But two kinds of fruits have been especially mysterious as Robin and Chopper's Devil Fruits never made it to the series officially, but now fans finally got to see a look at what Robin's Hana Hana no Mi and Chopper's Hito Hito no Mi looked like before they were eaten. Check it out!
Hito Hito no Mi (Choppers fruit) and Hana Hana no Mi (Robins fruit) illustrated for the first time from r/OnePiece
There have been a ton of Devil Fruit abilities over the series, but few have actually had their designs revealed. Not much is known about the origin of these fruits, but it's clear that each one has its own unique look and abilities. Robin's Flower-Flower Fruit indeed reflects its name as it's a blossoming lotus shape, and this is a good indication of the powers she gets after eating it.
Chopper's Human-Human Fruit is a bit more surprising, however, as its design does not really imply that it would give the eater human intelligence and comprehension skills. It looks like a stereotypical fungus. But with this look, it does explain why Chopper seemed to eat it at random because he was starving and out of options. It doesn't seem like too dangerous of a fruit off the bat.
There still need to be plenty of things explained about Devil Fruits and why they are so prevalent throughout the seas, but who knows how long it'll be before Oda explains it all. It could be another 20 years!
Eiichiro Oda's One Piece first began serialization in Shueisha's Weekly Shonen Jump in 1997. It has since been collected into over 80 volumes, and has been a critical and commercial success worldwide with many of the volumes breaking printing records in Japan. The manga has even set a Guinness World Record for the most copies published for the same comic book by a single author, and is the best-selling manga series worldwide with over 430 million copies sold. The series still ranked number one in manga sales in 2018, which surprised fans of major new entries.