These lilies* really were a surprise to us because we didn't know we had them! Last fall my husband ran across some bulbs when we were working on a bed, and replanted them. We just assumed they were more daffodils, but this is what we got instead! They must have been in need of division and fresh soil since they hadn't bloomed in years. Surprises like these are what make gardening so much fun.
*They aren't actually lilies at all, but members of the amaryllis family, which is why latin names like Lycoris squamigera come in handy and help prevent confusion.