As Yusuke walked under a wall, a rival gang jumped on top of him and started pummeling him. Since Yusuke was caught unawares, it took a few seconds for him to throw them all off. After they ran off, Yusuke continued walking. A few minutes later he stopped as he felt very strange. He began to grow. He grew until the tallest building was at waist height at about 256'5'' tall.
"Whoah! I guess that ring works after all! I wonder how tall I am?"
He checked the ring and it told him his current height.
"I'm not even 400' tall yet! I think it would be better if I left the city for awhile." He carefully stepped around buildings to the outskirts of the city. There, he sat down to wait it out.

Meanwhile, Koenma was watching the whole thing.
"Hoo boy. I guess that ring I gave Yusuke was far too powerful. I'd better send someone to get it from him."
So Boton flew out to retrieve the ring.