0 (Kirby)

0, alternatively spelled as Zero, was the main antagonist for a portion of the Kirby series, whose influence continues to affect the series. It is the creator of Dark Matter.

Kirby's Dreamland 3
After the defeat of Real Dark Matter, 0 launched an invasion of Pop Star and possessed multiple regions. Kirby one by one liberated these lands, then encountered the Dark Matter possessed Dedede. Kirby drove it out of him and back to the Hyper Zone where 0 resided. After Kirby and Gooey defeated the Dark Matter using the Love-Love Stick, 0 revealed itself and attacked Kirby. In a desperate attempt to kill Kirby, 0's eye detached from its body, becoming a small, bloody eyeball. Kirby defeated this, and 0 was defeated.

Kirby 64: The Crystal Shards
0 later returned as 0² and served as the main antagonist in Kirby 64 and the true final boss. In this game he has an angelic appearance and a bandage on his head (which is likely a reference to him pulling his eye out at the end of Kirby's Dreamland 3). In order to face him you must collect all 74 crystal shards, otherwise Miracle Matter serves as the final boss.

Description
0 is either a large white sphere with a singular entirely red eye, or just an oversized eye ball.

Trivia

 * Several fans have considered 0 one of the scariest bosses of all time in both of his appearances.
 * Some fans have pitted against 0 against Giygas and Flowey, as both are known for being incredibly creepy.
 * 0 is similar to Giygas in a few ways:
 * Both are final bosses of their respective games.
 * Both are aliens.
 * Both are uncapable of feeling emotion.
 * Although, it should be noted that Giygas was trained to be unfeeling, as human emotion was deadly to him.
 * Both are known for being extremely disturbing and scary.
 * Both try and become friends with the main character, only to lose their sanity after a brief moment.
 * Both are the final bosses of two Nintendo games.
 * Both are in charge an alien race (Giygas: Starmen, 0: Dark Matter).
 * Oddly enough, a cactus seems to portrude from 0², which is his weak point.
 * Some fans have speculated that Dark Mind, the main antagonist of Kirby & the Amazing Mirror, is an alternate-dimension version of 0.
 * Many later villains in the series bear resemblance in a way to 0.
 * Dark Mind appears as a giant ball with an eye.
 * Drawcia Soul appears as a giant ball with a mouth that strangle resembles an eye.
 * Dark Nebula is a sorce of darkness, with the power of possessing others.
 * Magolor, when defeated, is completely overtaken by the Master Crown and has a giant eye with a red pupil in his mouth, which almost completely resembles 0.
 * Also the fact Magolor is in charge of a race of monsters.
 * Some fans have theorized the Master Crown in Return to Dreamland had a portion of 0's soul within it.
 * Because 0 hemorrhaged and bled on screen (and shot blood at Kirby as attack, as well bursting of the rest of his body in a gruesome, gory scene), he has often been depicted the most gruesome character in Kirby history.