Part One:
"So you've choose to be Bulbasaur, hm? A safe selection!" Professor Coak exclaims. "Hop into the machine and we'll soon have you on your way!"
He takes the short blue reptile from her cafe and straps her into the Pokeswapper beside you with restraints about her wrists and ankles. A helmet is placed over your head. There is a burst of searing light and pain...
When you open your eyes, your human body is already rising from the chair beside you. You stare down past your bulbous, blue breasts, seeing your limbs buckled to the arms of the chair. You just hope the absence of opposable thumbs won't hinder the use of your Pokedex. The Bulbasaur in your body stares at her hands and flexes her long, pink fingers.
"Finggguuurrs," she remarks in a low growl. Her eyes light up, delighted at being able to enunciate something other than the same three syllables for the first time in her life. "Finggguuurrs!"
You look at the Professor in alarm. "Assaur!" you blurt. "Assaur!"
"Looks like not everything carried across in the swap," the Professor chuckles. "Ah, it happens sometimes!"
With a goofy grin on your face, the Bulbasaur lowers herself onto all fours and lopes out of the laboratory. Professor Coak unbuckles you and lifts you down to the floor. You stumble, your legs pivoting clumsily at the hips, and fall forward onto your front paws. It appears you'll have to make do with a quadrupedal stance on your travels.
Regardless, adventure awaits! You waddle for the door.
Professor Coak's foot blocks your way. "Ahem. Aren't you missing something?"
"Assaur?" you say up at him.
"Haha! 'Assaur' indeed! And significantly less 'bulba'!" He taps a finger against your back... Your bare, exposed back. "Normally a Bulbasaur receives a seed at birth, imparted from the mother during gestation, a beautiful symbiosis of plant and animal. This poor specimen, alas, did not. They're rare - even more so since they never survive long in the wild without their bulb for defense, so we can hardly let you out into the world without one. They say there is a way for a mature specimen to be implanted with a seed, though it has never been witnessed. It is a private, personal ritual conducted in remote forest clearings far from human eyes."
The ground beneath your paws trembles. The windows in the greenhouse wing of the laboratory rattle in their frames. Something huge and heavy is lumbering closer. The trees growing in the greenhouse bend and snap like sticks of celery beneath the hulking bull-Venusaur, as it maneuvers its bulk through the laboratory. The pungent, sweet musk of pollen emanates from the blossoming flower on its back.
Professor Coak gives you a delighted wink and reaches for a camcorder. "Venusaur here has agreed to pollinate you with his seed. To de-deflower you, if you will, haha! And I'll be here to record it for posterity! Aren't we lucky?!"
Thick vines tipped with knobbled protruberances emerge from the Venusaur's bulb and ensnare your limbs. The creature moves closer, its huge muscular belly scraping against the floor beneath its squat limbs. Two vines coil up your thighs, their touches like slow caresses. A third spirals up your arm and plunges towards your mouth with more businesslike intent.