Gokhan is the immensly powerful fusion of Goku and Gohan.
It is the Potara Fusion counterpart of Kuhan
Gokhan has immense power, multiplying Mystic Gohans powerlevel with Goku's. Gohkans base form is around the level of Super Saiyan God Goku when he fought Beerus. Gohkan can go up to SSJ2 whith ease since both of his fusee's could go SSJ2.
Gohkan wears the signature turtle hermit gi that both Goku and Gohan wore, with the exception it has no markings on it. Gohkans hair looks like a shorter version of Goku's SSJ hairstyle.
Goku and Gohan almost fused in the buu arc Dragon Ball Z.