[It could have happened any number of ways. This was Gravity Falls, after all. It was basically a primordial sea of weird, from which all manner of freaky and unbelievable things emerged.
It actually could've happened in a worse way than it did, too. Well, probably, anyway. As it is, it's still Dipper's fault, but only obliquely so. After all, it was Grunkle Stan who had told the twins to stop watching a three-day Duck-Tective marathon and go outside to get some fresh air. (Dipper was pretty sure that Stan just wanted the TV to himself--the man could only take so many missed episodes of Baby Fights, even if he'd started to come around about Duck-Tective.) And it was Mabel who, in the middle of their walk to get fresh air, had tricked a fairy into giving her some of the anti-aging cream the little fae was milking from a tiny herd of tiny unicorns with tiny razor-sharp sharklike teeth. And it was Soos who had gotten Mabel's bottle mixed up with the drinks he'd gotten from the vending machine to share with the kids.
But it was Dipper who had given up his drink when Wendy had come in for her shift, looking hot and exhausted from the bike ride to the Mystery Shack. And it had just so happened that his drink...was actually Mabel's bottle of anti-aging cream.
A sip every now and then was supposed to 'preserve your youthful good looks' as Mabel put it; but Wendy had basically chugged the whole thing all at once...and the results were pretty immediate. No sooner had Wendy said, "Man, I feel kinda weird," then the change began. Dipper could only watch in wide-eyed horror as the years began to melt away from the older girl, until he was looking down--yes, down--at a probably nine-years-old or so version of Wendy. (He was actually pretty relieved, though. He'd been afraid that he'd have to watch Wendy getting younger and younger until she finally turned into a baby and then disappeared altogether. He didn't know HOW he would've undone THAT.)
IN ANY CASE, TL;DR
HI DIPPER, THERE IS A NINE-YEAR-OLD REDHEAD WHO DOESN'T KNOW YOU WANDERING AROUND INSIDE THE MYSTERY SHACK GIFT SHOP, POKING THINGS THAT PROBABLY SHOULDN'T BE POKED.]
Suddenly a Child, of course, as discussed! <3 Also, sorry for the book.
It actually could've happened in a worse way than it did, too. Well, probably, anyway. As it is, it's still Dipper's fault, but only obliquely so. After all, it was Grunkle Stan who had told the twins to stop watching a three-day Duck-Tective marathon and go outside to get some fresh air. (Dipper was pretty sure that Stan just wanted the TV to himself--the man could only take so many missed episodes of Baby Fights, even if he'd started to come around about Duck-Tective.) And it was Mabel who, in the middle of their walk to get fresh air, had tricked a fairy into giving her some of the anti-aging cream the little fae was milking from a tiny herd of tiny unicorns with tiny razor-sharp sharklike teeth. And it was Soos who had gotten Mabel's bottle mixed up with the drinks he'd gotten from the vending machine to share with the kids.
But it was Dipper who had given up his drink when Wendy had come in for her shift, looking hot and exhausted from the bike ride to the Mystery Shack. And it had just so happened that his drink...was actually Mabel's bottle of anti-aging cream.
A sip every now and then was supposed to 'preserve your youthful good looks' as Mabel put it; but Wendy had basically chugged the whole thing all at once...and the results were pretty immediate. No sooner had Wendy said, "Man, I feel kinda weird," then the change began. Dipper could only watch in wide-eyed horror as the years began to melt away from the older girl, until he was looking down--yes, down--at a probably nine-years-old or so version of Wendy. (He was actually pretty relieved, though. He'd been afraid that he'd have to watch Wendy getting younger and younger until she finally turned into a baby and then disappeared altogether. He didn't know HOW he would've undone THAT.)
IN ANY CASE, TL;DR
HI DIPPER, THERE IS A NINE-YEAR-OLD REDHEAD WHO DOESN'T KNOW YOU WANDERING AROUND INSIDE THE MYSTERY SHACK GIFT SHOP, POKING THINGS THAT PROBABLY SHOULDN'T BE POKED.]
Whoooooooaaaa! What's this weird thing?
[POKE POKE]