Some Thesaurus words for "unexpected" - abrupt, accidental, astonishing, chance, fortuitous, impetuous, impulsive, instantaneous, out of the blue, prodigious, staggering, startling, stunning, unanticipated, unforeseen, unlooked-for, unpredicted, wonderful.
As you can see some pretty amazing words. For this photo, I really liked the unlooked-for wording because it was not what I expected to find at all on a tractor seat. I loved the random holes, the wonderful elliptical shape, interesting value changes and the color of the vibrant grass giving the rusted element so much life. So when you see those rusted pieces of machinery in the tall grass, go in for a closer look because you never know what you might discover.