King Kong Gun

King Kong Gun is 's Final Smash in Super Smash Flash 2.

Overview
When performed, Luffy enters Gear Fourth, then enlarges his fist to deliver a huge, long-ranged blow called Gomu Gomu no King Kong Gun as Japanese text splashes out.

Origin
During the timeskip in One Piece, Luffy develops a technique called Gear Fourth to combat the large beasts on Rusukaina, and made its official debut in chapter 784 during his battle with Donquixote Doflamingo in Boundman form. It combines the powers of the Gomu Gomu no mi and Busoshoku haki to create a powerful form that utilizes compressional strikes opposing his usual stretching abilities. The form also uses alternative forms such as Tankman and Snakeman.

Gomu Gomu no King Kong Gun (ゴムゴムの) is one of Luffy's most powerful attacks in Boundman. He preforms this by projecting more haki into his arm to enlarge his fist to a greater size then compresses and launches it in a similar fashion to Gomu Gomu no Kong Gun (ゴムゴムの) to deliver a devastating blow to his opponent. Luffy first used the technique to break through Doflamingo's Spiderweb and God Thread techniques and defeat the Shichibukai by sending him deep below the city due to leveling and folding the city below themselves.