During the Prohibition Era, moonshiners had to be pretty crafty to keep their activities under wraps. Still, the authorities were bound to sniff them out from time to time, so distillers and smugglers crafted a clever getaway vehicle: cow shoes. These pieces of fancy footwear would leave hoofprints instead of footprints, which no policeman would think to pursue unless there was some sort of hooch horse on the loose.

A 1922 article from a Florida newspaper called The Evening Independent ran a piece on the development:

Tampa, May 27.—A new method of evading prohibition agents was revealed here today by A.L. Allen, state prohibition enforcement director, who displayed what he called a "cow shoe" as the latest thing from the haunts of moonshiners.

The cow shoe is a strip of metal to which is tacked a wooden block carved to resemble the hoof of a cow, which may be strapped to the human foot. A man shod with a pair of them would leave a trail resembling that of a cow.

The shoe found was picked up near Port Tampa where a still was located some time ago. It will be sent to the prohibition department at Washington. Officers believe the inventor got his idea from a Sherlock Holmes story in which the villain shod his horse with shoes the imprint of which resembled those of a cow's hoof.

[h/t Kottke]