Is that the same movie where there’s a hot bikini girl on land but when she’s in the water she turns into a giant sea turtle monster or she controls some giant sea turtle monster.
And somehow at the end some poor black guy gets tangled up in ropes around the giant sea turtle monster and he begs some other guy for a knife so he could kill himself but the guy doesn’t give it to him in time and the movie ends with the sea turtle monster dragging him under the water and him slowly drowning as he is dragged along
I saw the same movie when I was like 5 and it always stuck with me
That was The Bermuda Depths.
http://www.imdb.com/title/tt0077223/
The black guy was Carl Weathers.