A key hiding rock is hilarious as it is useful. They may have been eclipsed by fancy modern lockboxes in recent years, but we consider them old reliables that have a special cartoonish charm that other key boxes lack.
They also make great paperweights, money stashers or secret ashtrays if you're a secret smoker ;)
Details: Each rock slightly differs in shape and color and may not look exactly like the one photographed.