If you've never heard of cucamelons before, definitely look it up. The cucamelon is also known as the 'mouse melon' or the 'Mexican miniature watermelon'. It's a vine plant that can be grown in or outdoors in a sunny spot and indeed does have little fruit that look like watermelons, but taste like sour cucumbers.
If you'd like to try growing some cucamelons, we have these brilliant seed kits from New Leaf Nurseries in North Wales. These are really special products, packed plastic-free by Paul down to the tape and hand-stamped.
If you'd rather try, not grow the cucamelons, they also make a great gift!