Jim then scanned around the mall for someone to try it out out on. He spotted a young boy, looked to be about the same age at 12. The boy was looking for shoes for the start of school, but Jim knew that he could mess with him quite a bit. But how to do it? Releasing and inflating the balloon, he whispered "control that boy's awareness to his changes" and then deflated it fully. Now he could change the boy.
As the boy moved behind a clothes rack, Jim wished he could see him better. Then he had an idea. "Control that boy's size" he whispered to the balloon. Then he began to slowly blow into the balloon.
As he blew into the balloon, Jim's eyes widened as the boy's head seemed to rise out of the shelves. Jim stopped blowing and pinched the neck of the balloon. Whereas before, only the top of the boy's hair was visible, almost his whole head was popping out of the shelves. Jim estimated that he now had to look slightly up at the boy if he were next to him, which would make him about 5'1" or so. Jim began to blow into the balloon again.
Slowly, Jim saw the boy's head began to rise again, coming further and further out of the shelves. Suddenly he heard two ripping sounds, but the boy's clothes weren't falling off, although Jim noticed that the boy's shirt (which was now barely visible over the shelves) was tight in the shoulder region, as he had also become wider and not just taller.
Not even being careful this time, Jim blew another big breath into the balloon. Instantly the boy's head shot up further, easily clearing another several inches in height. With a start, Jim saw that the shirt was starting to tear at the shoulders under the strain.
Now that more of the boy's body was showing over the shelves, Jim was startled. Using the size adjective meant that the boy had not only grown proportionally, but that he was actually more muscular as well. However, the boy's head remained basically unchanged, although it had also slightly grown. It almost looked comical, the features of a young boy on the body of a late teenager.
Just because he was curious, Jim inhaled as best he could and blew one last huge breath into the balloon. Right before his eyes, the boy quickly gained even more height and size. The boy's shirt ripped at the shoulders, and barely managed to stay on with a couple threads holding it on. Almost the entire torso of the boy was visible above the shelf now. Jim had to crane his neck just a bit to keep looking at him.
Just then, the boy found what he was looking for. He walked out from behind the shelf and Jim realized what the ripping sound had been earlier - the boy's feet had ripped through his shoes. Even then, it clearly didn't bother the now huge teen. Jim realized that not only did the boy tower over him, he towered over almost everyone else in the store! Might have overdone it a bit, he thought. Unpinching his fingers just a bit, he let out a bit of air and was relieved to see the boy start to slowly shrink. He stopped it before he started however, as he wanted the boy to stay fairly tall. He estimated the boy was at least ten inches taller than he was before, around 5'8".