Snapper will take a finger off! My oldest son can testify to the truth of that statement. He had to have one of his finger tips reattached after a bite. Much larger than your friend though.
My grandfather, dad, and I used to fish Solider Creek at the mouth into Dirty Bird a lot when I was growing up. We would hike in with chest waders on after a good rain and fish in knee to hip deep water along the sides of the creek for catfish. Every now and then you would feel some pretty big snapping turtles bump into you as they rode the current downstream. We saw more than a few that I have no doubt could completely remove a finger without much effort.
They would also really fight you if they claimed your stringer while you were away.