"I wish John and I would trade ages!" Mikey practically shouted in his excitement.
After the obligatory bling and a moment of dissociation from his body, Mikey was able to look upon his new self. He was now 16, exactly as John had been. He found he liked how much he grew up. He had to be 6'6" at least and weigh somewhere between 250 and 300 lbs of muscle. He was much larger than John had been, and couldn't help but smile at the fact that even as things were he'd have easily been able to beat up John in a couple years.
"Damn it Mikey!" Mikey could hear a child, who could only be John, shout from the kitchen. Apparently, in his excitement, Mikey had said his wish loud enough to be audible to his now younger brother.
A moment later, the small child Mikey heard slammed the door open. He stood maybe 4'3" and weighed about 60 lbs, average enough stature for a boy of 8 as John now was but still significanly smaller than his mammoth of a brother.
"Give me the stone!" John demanded in his childish voice.
"I don't think so Squirt!" Mikey said as he pushed John back with his right hand. He was surprised by his new found strength as John flew back several feet.
"Damn it Mikey this isn't funny! This is really serious stuff you're playing around with!" John went on. Mikey just laughed at his brother's protests.
"This isn't funny!" John insisted, "you can't be a 16 year old guy and I can't be an 8 year old boy!"
John should have been more careful of what he said in his current predicament, because all he did was give Mikey an idea.
"If you can't be an 8 year old BOY," Mikey said with a devilish grin, "then I wish..."
