In 2012, the art world gasped in horror when a disastrously amateur restoration of Elías García Martínez’s fresco of Christ in agony, Ecce Homo, came out looking like a cross between a pained potato and a frilled monkey. But the furor quickly turned to delight. People worldwide cheerfully renamed the image Ecce Mono (“Behold the monkey”), or pasted the same potato face on the Mona Lisa, The Scream and the entire cast of The Last Supper. The DIY restorer, 81-year-old Cecilia Giménez, became famous, and her town of Borja, Spain became a destination. Hundreds of thousands of visitors have visited over the last eight years, hoping to see Giménez’s simian Jesus. Adding to the fun, American composer Paul Fowler and librettist Andrew Flack produced a comic opera about the event, B...