Talassophobia V

you're fishing calmly, when suddenly you see splashes and a giant black tail going into the water, you decide to check what the hell it is, and dive into the water to check

it was some day in some year eleven
you went fishing with your grandfather
Grandpa immediately got completely drunk
and you fished hoping for a huge fish
when suddenly I began to notice strange things, splashes, some traces of claws, a black tail flashing, someone eating the catch from your fishing rod