The following contains spoilers for One Piece "Whole Cake Island" Arc, available in English from Viz Media.
The "Whole Cake Island" Arc in One Piece puts Sanji in the spotlight. Not only does the Straw Hat Pirates' cook manage to snag himself a wife but fans are finally provided with his royal backstory. However, the arc isn't necessarily filled with sunshine and roses. Sanji mostly spends his time being threatened one way or another, both by Big Mom and his biological family. Even his supposed bride is in cahoots with his assassination attempt. But the events take a different turn when Pudding reveals her supposedly gruesome third eye.
The young Charlotte expected Sanji to be fraught with terror. But it didn't occur to her that Sanji's obsession far surpasses the kookiness of an additional eyeball, resulting in Pudding falling in love with Sanji instead. While this development is supposed to be one of the biggest plot twists during the arc, it has actually been spoiled more than a hundred chapters prior to the "Whole Cake Island" Arc.
Pudding's Third Eye Was Introduced Earlier In The Story
While Pudding's appearance did come as a surprise, there may be some One Piece fans who have predicted the revelation. After all, it isn't the first time Pudding revealed her cyclopean third eye. In fact, her first appearance in the manga isn't during the "Whole Cake Island" Arc but during the "Fish-Man Island" Arc. At the time, the Charlotte daughter didn't even bother hiding her extra eye. Given that she only appeared in a single panel, most fans have likely glossed over her appearance.
The reveal happened after Luffy and the Straw Hats defeated Hody Jones and his cronies. King Neptune reasonably decided to grant their saviors a banquet, serving them every delightful dish they can offer. That included the sweets that were supposed to be tributes for the Big Mom Pirates. When Big Mom heard about the news of the missing sweets, the Emperor was unsurprisingly upset. Pudding was present when Bishop Bobbin relayed the unfortunate news, and her third eye was already shown in its full glory at that moment.
Pudding's Third Eye Is Integral To Her Character
Pudding's relationship with her third eye goes beyond its role in the assassination plot and her initial intentions to deceive Sanji. The negative experiences and societal pressures she faced due to her unique feature have deeply impacted her self-esteem and perception of herself. Throughout her life, she has been subjected to mockery and ridicule, which fueled her insecurity and disdain for her third eye. That's why Pudding is caught off-guard when Sanji genuinely finds her third eye attractive.
In addition to that, Pudding's third eye isn't just an aesthetic deviation. Pudding having a third eye is the result of being the child born between Big Mom and a member of the rare Three-Eye Tribe. It is said that she has the potential to awaken a certain ability, which is also supposed to be Big Mom's key to deciphering the ancient Poneglyphs. As to when that will occur, only future chapters of One Piece can tell.