So, I was in the front yard on Saturday, and I saw this for the first time!

It's a volunteer Red-seeded Citron watermelon. The seed it grew from was from a plant that I grew in 2015. The fruits kept better than most winter squash. It volunteered last year, too, but this year's plant is much larger (and this year there's just one plant).
A family member had been watering it, apparently.
Location: SW Idaho, USA
Climate:
BSk
USDA hardiness zone: 6
Elevation: 2,260 feet
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