Context: Saint Bernard and the Virgin is an oil painting by Spanish artist Alonso Cano (c. 1645–1652), depicting the Lactatio Bernardi miracle in which Bernard of Clairvaux receives milk from the Virgin Mary as a reward for his theological work. The painting is now held in the Museo del Prado in Madrid.
Before reading the description, I thought it was an unfortunate, yet hilarious scratch on the painting.