A makeshift tarpaulin body bag left on the road’s shoulder signaled something nefarious, something noir. In the crepuscular light, a scrawny orange cat—a common sight on Hydra—fished under the tarp and apparently found something it liked. Soon a woman ran over to shoo the cat away, like some PA on a movie set. As dawn broke over Mandraki Bay, guests began to gather along a squat stone wall to peer into the water below, waiting for the commencement of Matthew Barney and Elizabeth Peyton’s Blood of Two, 2009, the artists’ first collaboration.

In that bag, it turned out, was a dead shark, though