Back in the days of 30-40' visibility in Lake Travis around Austin, TX, we used to frequent Don Brode's Scuba Park. A private cove for instructors and their classes only. Don had a great setup with docks, a barge that he would move sunken boats around the cove with, compressor, had to use his steel 72's.
Anyway, it was common for us to feed hotdogs to the fish with students. Once were were standing on a 48' houseboat at about 70', feeding the fish, when two huge channel cats came in and started circleing. One was about 6' long, the big boy around 8'. They circles for about a minute when the big guy suddenly turned, heads stright for my buddy Marc. As he got close to Marc he opened his mouth which looked like a grage door opening. Marc was standing with his hand above his head holding a whole hotdog. The volume of water going into that mouth so suddenly not only sucked the hotdog in but pulled Marc's glove halfway off his hand. Pretty cool.
I've also seel a tail about 14"-16" tall tail in Lake Waxahachie off Soldier Bluff. Vis was about 12" (yes inches) and we were at 80'. We decided to leave.
Yes there are big cats in the water. Usually nothing to worry about.
"They mostly come out at night. Mostly."
Name the movie.