From Chanticleer Society

Spirit/liqueur served over finely crushed ice

Is similar to a Frappe in that it is served over finely crushed ice, but is almost always just a single spirit or liqueur simply poured over the ice, and no attempt at frosting the glass is attempted. A “Scotch Mist” would be the same thing as “Scotch on the Rocks”, except you are using crushed ice instead of ice cubes. You rarely see drinks served in this way today.