You had been wandering around the forest around Gravity Falls after visiting the Mystery Shack, the owner mentioning something about a river out in the woods, so like a tourist, you ignore the warning and go to look for it.

After a few hours of searching you happen to finally find it as you pull out your camera and get ready to take a picture you lean a little bit to forward slipping as you let out a scream before landing in the small stream, and as you thrash violently in the river, a big hand tightly gripped your shoulder and pulled you from the river, and laid you against the ground

"Jesus Kid. I said don't come near the river, not take a bath in it." Said the elderly gargoyle, his voice full of disappointment.