The phrase "black turtle" represents the idea of a secretive and cautious person or organization that moves slowly and is difficult to approach or understand. Full definition
I wore my new black turtle neck body suit with this cool tie detail on the front. (petiteandhungry.com)
I also use red and white kidney beans for chili, black turtle beans, and black eyed (peas) beans on a frequent basis. (thehealthyhomeeconomist.com)
There are so many dishes that can be made with just a can of Black turtle beans, being desserts to stews, having a couple of these in your cupboard, can be a lifesaver. (thefreshedit.com)