Nintendo's lovable pink fluffball has been around for over 20 years since his debut in Kirby's Dream Land on the Game Boy. Since then, Kirby has found himself in many adventures that have forced him to adapt to various situations, from getting turned to yarn to riding a giant robot through space, and that's not even getting into his signature copy ability, which changes both his appearance and capabilities in battle.
Throughout Kirby's storied history, the hero of Pop Star has gone through many changes from great to small to incredibly strange, but always maintaining that adorably iconic silhouette. Here is a quick look at the various weird aspects of Kirby's appearance and biology and how it has changed from conception until now.
He's Only Eight Inches Tall
Despite being powerful enough to eliminate gigantic magic space monsters and inhale black holes, Kirby's only officially listed height places him at under a single foot. This little factoid comes from a character profile promoting the release of Kirby 64: The Crystal Shards in the Japanese-only Nintendo Online Magazine.
This listing should be taken with a grain of salt, as in the same game, it's shown Kirby actually reaches about half the height of his friend Adeleine, who is, for all intents and purposes, a normal human girl (albeit one that can paint pictures that come to life). Super Smash Bros. fans should also be aware that height hardly matter when it comes to Nintendo characters, as Captain Olimar from Pikmin is barely the size of a quarter in his own game.
He Has No Skeleton or Teeth
Considering how rubbery and pliable the little guy is, this should be a given, but it has been officially confirmed that Kirby has no skeleton and no teeth. How Kirby manages to hold himself up and maintain his shape is still a mystery.
The anime Kirby: Right Back At Ya! (simply titled Kirby of the Stars in Japan) had an episode titled "A Dental Dilemma" where a dentist monster created by Nightmare Enterprises tries to find teeth in Kirby's mouth to clean, only to find he has none. Not that he needed teeth to begin with, since he vacuums up mountain-sized cakes and monsters on a daily basis.
He Was Going to Be Yellow
Masahiro Sakurai, Kirby's creator (as well as the director of Super Smash Bros. and Kid Icarus), always intended for Kirby to be pink. But apparently something as simple as Kirby's color was in dispute, as Mario creator Shigeru Miyamoto himself wanted Kirby to be yellow.
This turned out to be kind of a moot point at the time, since Kirby's Dream Land was on the original Game Boy, which couldn't render color. The U.S. box art and instruction booklet colored Kirby white to match the sprite in-game, and Kirby wouldn't be pink until the official NES sequel, Kirby's Adventure. Still, Miyamoto got his wish half-granted, as in multiplayer games featuring more than one playable Kirby, the second Kirby is yellow more often than not.
He Doesn't Seem to Have a Biological Sex
Kirby is most often referred to with male pronouns in localization, and his name is rather masculine-sounding. But in Japan, Kirby is referred to almost exclusively via gender-neutral pronouns alongside most of his supporting cast. The manga (which is of dubious canon like most things Nintendo-related) does seem to treat Kirby as male, and he apparently has Dream Land 3's ChuChu as a girlfriend.
Masahiro Sakurai himself isn't quite sure what Kirby's sex is. He did, however, jokingly suggest that Kirby and Pikachu may both be female on a Smash Bros. page in response to fans surprised by the fact that Metroid's Samus Aran is a woman without further elaborating on it. Kirby's official Twitter page in Japan has implied Kirby may be genderfluid, as the character has dressed up as an Empress doll for Valentine's Day and was depicted alongside men for White Day.
Kirby Was a Placeholder
Kirby wasn't always meant to be a strangely cute blob creature. Masahiro Sakurai had, in fact, only intended for a nearly featureless ball thing to be a placeholder model for a game he titled, "Twinkle Popo." The planned hero, named "Popopo," was supposed to be quite different from Kirby, though only concept art featuring Kirby are known to exist.
Sakurai eventually grew fond of his placeholder model and decided to replace the planned character with Kirby. However, he wouldn't be called "Kirby" until much further into development, still maintaining the original protagonist's name of Popopo until Dream Land was officially released in Japan.