First of all, if a “shark” Sage Mode existed, it’s hard to believe that Naruto author Masashi Kishimoto never mentioned it, neither in the manga nor in the franchise’s databooks.

It's a move that kept growing and changing throughout the course of Naruto, Shippuden, and Boruto ... all involving wind-nature chakra. Entering Sage Mode gives Naruto access to senjutsu chakra ...