Marcy considered things for a little while before smiling. "Why don't you become me?" she asked, finally.
Ty was taken aback, "What? Beccome you?"
She smiled, "Sure! It would be perfect. You don't have a family you care about, you've certainly told me that enough times. This would give you a family to be a part of!"
Ty leaned back, "But then I'd be a girl." he said matter-of-factly.
Marcy laughed, "What does that matter? You can be anyone, anything! You'd only be female when it mattered to maintain the charade! If you wanted, you could even alter the reality so that I was born male. Keep your life, but so my parents wouldn't be childless!"
Ty actually considered it, and considered it hard. He wouldn't miss his foster family in the least. Marcy had parents that were loving, though very distant and a bit cold, but they were far better than what he had. Besides, once he was settled in, he could alter things a little so they were a bit warmer.
He looked around the room, seeing the frills and trappings that came with the life of a teenage girl. He could alter it all with a thought into a boys room, but somehow this seemed like an interesting adventure.
Grinning, he looked back at Marcy, "Okay, ground rules."
She perked up instantly, "Shoot!"
"If I do this, your life becomes mine, totally. If you don't like who I'm dateing or what I'm doing, tough!"
"Deal!"
"I'll give you the ability to communicate directly to me mentally, so we can talk about things and so you can help me be a better you, but don't abuse it. It only takes a thought for me to make you nothing but a dumb dog, remember."
She wasn't so fast this time, but finally said, "Deal. Anything else?"
"If I decide to make this a male life instead of female, that's my choice. Remember, there isn't much you can do about it. And if I decide that this whole thing is too much, I can end this anytime."
She sighed, clearly unerved but excited, "Deal. What else?"
Ty thought, he was sure that there was more, or things that would come up later, but for now this was fine. "What kind of dog do you want to be?"
She smiled, "Golden Retreiver."
"Female?"
"Yes."
Ty paused, "Do you want to have puppies someday, or be fixed?"
That stopped her cold, and for the first time the reality of being a dog seemed to sink in. She wouldn't have human kids, she'd have puppies. Ty let her think for a few minutes before she finally nodded, "If I'm going to be a dog, I might as well take the full experience. Don't let them fix me."
Ty nodded slowly, then looked her. Her clothes vanished and her skin started to grow golden fur. Her tail wagged as it grew out, as she fell to all fours. In mere moments, Marcy was a dog. Ty concentrated a moment to alter reality, to make sure the family always had a large dog.
"What name do you want, girl?" he asked, "You can't be Marcy anymore."
She looked over herself, delighted about what she was, before looking back, "Just call me Lady," she said into his head. "Now, what about your end of the deal?"
Ty smiled, and with little more than a thought he assumed Marcys body. He was surprised how easy it felt, how little the differences were right off the bat. With a few more thoughts, he aquired all her memories, mannerisms and thoughts. No one would know that someone new was in control.
And with another thought, he erased Ty from existance. He was surprised how easy that was, too.