In the Infinite Tsukuyomi, Shikamaru Nara looked to the left to see Asuma Sensei and Kurenei feeding a crying Mirai Sarutobi. Then he looked to the right to see his father getting chewed out by his mother. "Marriage is such a drag," he said.
"Indeed," his female friend, Temari agreed.
They both decided there and then to stay friends.
In the real world, Shikamaru, along with all the rest of the world, was cocooned and tied to the Shinju Tree. In a matter of years, he wouldn't have to worry about marriage and such silly things anymore. Not when he's become White Zetsu and fight for Princess Kaguya.
The first thing to go were his clothes, leaving him completely naked in his cocoon.
The next thing to go after a few years to go was his chakra, and in time, his body became shriveled and his black hair lost its coloring, a sign he was being drained.
As more of his chakra was drained, he began to drain him of his will along with his thoughts, his knowledge of the Shadow Paralysis Jutsu, his memories of his father and Asuma Sensei, everything. Even his secret admiration for Temari. Eventually, he began to hear a woman's voice, telling him that he won't have to worry about anything ever again. All he had to do was obey her unquestionably. Somehow, that didn't sound bad.
Eventually, what was left of Shikamaru was a mindless, withered husk. But thanks to the Shinju, he was still alive. Now he was ready for the next phase of the transformation.
Over the next couple of years, the cocoon slowly merged with his body, reforming it to make it more fit to be a soldier's. Soon, his skin turned white with jagged lines, his eyes turned yellow and his hair turned green.
Eventually, the body detached itself from the branch and dropped to the ground. Shikamaru was gone. In his place was White Zetsu. One of millions strong. And all of them loyal to Princess Kaguya Otsutsuki. At long last, Shikamaru Nara no longer had to worry about anything except serving his princess. That didn't sound like a drag at all.