It's true, you can't tell a book by its cover, and you can't tell what is in a person's heart by their appearance. I am reminded of the Home Alone movie where Kevin finds a friend in a rather shabby homeless woman. This lesson is taught to us from our childhood on, but we still pass judgments based upon looks, size, color; you name the quality and someone will use it as a basis of hard and fast fact.
And today, on a lesser playing field, the garden, I feel I have done it again. During today's early morning walk and review, I noticed that pumpkin is not looking like a pumpkin after all. But I made the earlier assumption it was a giant pumpkin plant based upon the plant's size. Looking at the developing fruiting body I would say this garden coup is being staged by a buttercup squash.