Jeff felt his hand tremble as he looked over the screen. He was sure this was perfect. It was everything he wanted. The right level of experience, the right level of time, the right level of intelligence.
He was sure nothing could go wrong.
He closed his eyes and hit enter. Then he opened his eyes...
It was suddenly dark, and he felt strange. The world moved around him and he could feel his body shrink to fit its new confines. He was an unborn calf!
Even as that realization hit, it was like his mind emptied. It was harder and hard to remember things that, for a fleeting moment, he tried to hold onto. Slowly, as time passed, he even forgot that he had forgotten. Jeff remembered little of his past, and none of it mattered.
Time passes and he felt a strong push, then another, as the warm water he floated in drained away. It wasn't long before his head was pushed out into the open, and then the rest of him landed hard on the grass in a field. Jeff sat their dazed and light headed. He... no, she, remembered a little. She was something called a cow. It was going to be a lovely, contented few years. She would make milk for her owners, and later new cows. Then she would be a human again.
Those thoughts drained away as she struggled to her four legs for the first time in this life, and felt a draw to the underside of her mother. She suckled for the first time, feeling the warm milk fill her belly. She was content.