At first glance, the strange black fruits in the photograph look almost like something from another planet. With dark, hard shells and pointed horns, they are difficult to recognize as food.

The fruits appear to be water caltrops, also known as water chestnuts, buffalo nuts, bat nuts, devil’s nuts, or singhara. They belong to the genus Trapa and grow in freshwater environments such as ponds, lakes, and slow-moving waterways.

Despite their unusual appearance, the inside contains a pale, starchy kernel that has been eaten traditionally in parts of Asia for generations. When cooked, it can have a firm texture and a mild, nutty or chestnut-like flavor.

However, water caltrops should not simply be eaten raw. Freshwater plants can carry microorganisms or parasites, including certain intestinal flukes. Thorough cooking helps reduce these risks.

Preparation generally involves washing the fruits, boiling or steaming them, allowing them to cool, and carefully removing the hard shell to reach the edible kernel. The kernels may be eaten as snacks or added to soups, rice dishes, stir-fries, porridge, sweets, or ground into flour.

It is also important to confirm the species and source before eating wild water caltrops. A photograph alone cannot guarantee identification or safety.

Interestingly, water caltrops are not the same as Chinese water chestnuts, which are produced by a different aquatic plant. Some Trapa species can also become invasive, so they should never be released into natural waterways.

These bizarre-looking fruits are a fascinating example of how traditional foods can look completely unfamiliar while hiding a nutritious, starchy center.