"I wish I was downstairs in the kitchen," Jon said. The stone glowed, and suddenly he felt his body changing. Oh no! he thought. It's happening again.
And before Jon was transported to the kitchen, he transformed into Biff Meadows, a jock who was the boyfriend of Sarah McMillan.
After he found himself in the kitchen, he looked down and saw that he was still wearing his mother's clothes (which looked completely out-of-place on his new muscular male body).
He had to get out of there before someone spotted him. And then he had to figure out what was wrong with the stone.