There's this one Naruto Shippuden flash game floating around, you know the kind you'd find on newgrounds or e621 back in the day, and it decides to fill in a blank the show left. The blank being the big pervert Sasori and what he apparently does to Sakura after that whole puppet master fight with Chiyo. Forget the hundred puppets technique, his real secret jutsu is something else entirely, a skill for mentally destroying girls through humiliation, and the game just cuts straight to him using these mechanical tentacles on her.
The animation is rough, like really rough, not smooth at all. It's almost jarring how it loops, but maybe that adds to the whole grotesque factory of it. She's just there, Sakura, the strong student of Tsunade, and she can't defend at all. There is no fighting back mechanic, it's just a scene that plays out. You just watch. The tentacles, they're these crude robotic things from Sasori's arsenal, and the whole point is how this powerful technic just leaves her completely helpless. I spent maybe too long trying to see if the animation would change if I clicked around, it doesn't. It's just that one repeating loop of her getting *** by puppet appendages.
It's a parody, obviously, and naming it a "hidden chapter" is a funny way to frame it, like some lost Toei Animation cut. The whole thing is built on that one cruel idea from the tags, humiliation is his favorite card. If you're into a specific flavor of naruto hentai where Sakura gets absolutely wrecked by a Akatsuki member's dolls, this exists. The artstyle is that recognizable early 2000s flash look, and it commits to its single, unpolished fantasy of Sasori's secret technique without apologizing. Just don't expect a game, expect a scene.