Kiwano Melon
The horned melon also called African horned cucumber or melon, jelly melon, hedged gourd, English tomato, melano, or kiwano, is an annual vine in the cucumber and melon family. Often known by its nickname in the southeastern United States - blowfish fruit - it is grown for its fruit, which looks like an oval melon with horn-like spines. The fruit of this plant is edible, but it is used as often for decoration as for food. When ripe, it has a yellow-orange skin and a lime green jelly-like flesh. The horned melon is native to Africa, and it is now grown in California, Chile, and New Zealand as well.
In Zimbabwe, this cucumber is called 'gaka' or 'gakachika' and it is primarily used as a fruit-snack, salad and rarely for decoration. It is eaten young, mature green or when ripe - bright yellow/orange (eaten at any stage of its development). It grows naturally in the fields and also in the bush. However, some people leave some to rot in the fields for next summer seeds/plants. Its taste has been compared to a combination of cucumber and zucchini or a combination of banana, cucumber and lemon. The seeds are covered in a gelatin-like substance. The skin is very rich in vitamin c and fiber. Before being eaten, adding a small amount of salt or sugar can increase the flavor.
I have had these before. This one, too, was very bruised up.
See the inside of a Kiwano or horned melon here: