The Accidental Watermelon

So...I may have accidentally bought a watermelon plant....that I may have somehow thought was an okra plant... I am a very novice gardener to begin with, but then I thought it wise to do a whirlwind trip through the Home Depot at 7 am on my way to work. Apparently, I was not fully caffeinated and in the morning sunlight my mind saw okra. In the car on the way to work I noticed the picture of the bright red juicy fruit pictured on the plant tag. Curious, I thought as I pulled the tag out of the plant. Then I flipped it over to read about my not-an-okra watermelon and the first line read..."Mammoth fruit can reach up to 125lbs!" Did I mention my garden is only 4ft x 8ft. The one thing it is definitely not is mammoth. Oh, what to do with my accidental watermelon!