The gesture caused her to drop the flashlight.

Its button was "set forward," so it did not go out as it fell.

Instead, it rolled in a semi-circle, casting its ray momentarily in a wide irregular arc as it revolved.

Then it came to a stop, against an outcrop of coral, with a force that put its sensitive bulb permanently out of business.
But, during that brief circular roll of the light, Gavin Brice caught the most fleeting glimpse of the sight that had caused Claire to cry out and shrink back against him.
He had seen, for the merest fraction of a second, the upper half of a man's body--thickset and hairy,--upright, on a level with the ground, as though it had been cut in two and the legless trunk set up there.
By the time Brice's eyes could focus fairly upon this very impossible sight, the half-body had begun to recede rapidly into the earth, like that of an anglework which a robin pulls halfway out of the lawn and then loses its grip on.
In practically the same instant, the rolling ray of light moved past the amazing spectacle, and less than a second later bumped against the fragment of coral--the bump which smashed its bulb and left the two wanderers in total darkness for the remainder of their strange pilgrimage.
Claire, momentarily unstrung, caught Gavin by the arm and clung to him.

He could feel the shudder of her slender body as it pressed to his side for protection.
"What--what was it ?" she whispered, tremblingly.