In this striking sculpture group, the Trojan priest Laocoön and his two sons struggle against a couple of deadly sea serpents. The gods sent the snakes to punish him for warning the Trojans not to take in the wooden horse the Greeks had so generously left behind.
Christian art tends to find something redemptive in suffering. This has none of that. There is only pain and fear, and no light at the end of it. The agony is so vivid that one commentator pointed out the expressions are anatomically impossible.
Find it in the Octagonal Courtyard of the Pio-Clementino.