There are 70 white mice in individual boxes set like tiles on the floor of a gallery on Manhattan’s Lower East Side. In clear plexiglass cages, designed to be stepped upon, they peer up underfoot in an exhibition exploring phobia.

To Natasha Millikan, a self-described mouse expert who squatted on the checkered floor on Sunday afternoon, her head pressed into her hands as around her mice shivered, chewed bits of wood or slept beneath her boots, it was an exploration of torture.

“Mice are prey,” she said into her cellphone, to the artist, Joseph Grazi, whom the gallery owner had called at her request after she arrived from Jersey City to protest the show. “They have the instinct to be terrified from anything up above them, any shadow. So at this point, these guys are just shutting down.”

Mr. Grazi disagreed. The animals, so-called feeder mice, he said, had been destined to be eaten by reptiles. Here in the shallow tiles beneath gallery-goers feet, they were well-fed and happy.