In the Twelve Labors of Hercules, Hercules carried Cerberus out of the underworld without using weapons.
Cerberus was the multi-headed watchdog of Hades. Eurystheus ordered Hercules to bring the creature to the surface alive, making this labor different from many heroic tasks that required killing or subduing a monster.
Hades agreed to release Cerberus on the condition that Hercules overcome him without weapons. Hercules protected himself with his lion skin and used his physical strength to restrain the dog. Once Cerberus was brought into the upper world, Hercules presented him to Eurystheus.
Ancient artistic and literary traditions do not always describe Cerberus identically, but the familiar version gives him three heads. The weaponless condition is the key distinction in this episode; it is not the same as saying Hercules used no protection at all.