Green horned melon fruit or Kiwano

Africa's traditional fruit, the kiwano is one of the few sources of water in the Kalahari Desert during the dry season. It is known as gakachika in northern Zimbabwe and is mostly eaten as a salad or snack. 

Any ripening stage is suitable for eating.
The fruit's flavor has been compared to mixtures of passion fruit and banana, cucumber and zucchini, or banana, cucumber, and lime. 

Although adding a little salt or sugar might enhance the flavor. The fruit's seed content may make it less convenient to eat than other common fruits. Some people also consume the peel, which is incredibly high in nutritional fiber and vitamin C.