This is what Wikipedia writes about the watermelon:
The Watermelon (Citrullus lanatus (Thunb.), family Cucurbitaceae) can be both the fruit and the plant of a vine-like (scrambler and trailer) plant originally from southern Africa, and is one of the most common types of melon. […] The watermelon fruit, loosely considered a type of melon (although not in the genus Cucumis), has a smooth exterior rind (green, yellow and sometimes white) and a juicy, sweet interior flesh (usually pink, but sometimes orange, yellow, red and sometimes green if not ripe).
For my metaphor, I’ll use the one with red flesh but orange and yellow would work too. I think most of us experienced the phenomenon when the project status is red but is getting greener and greener when climbing the management ladder. The project’s core is red but for the management it has a nice green paring, so it looks like a watermelon. This is why I call this phenomenon Watermelon Reporting. But why are we creating such reports and how can we avoid it?