Fill an old-fashioned glass with ice.
Pour the coffee liqueur straight down into the base.
Layer the vodka on top by pouring slowly over the back of a bar spoon.
Top with soda water poured the same way, keeping the three bands distinct.
Serve with a straw pushed to the bottom and drink it in one continuous pull.
An American bar-trick drink from the 1980s. The straw is not decoration: sip it normally and the layers collapse into a weak Black Russian instead of delivering the intended sequence.
My Bar Shelf reads your shelf and shows you every cocktail you can make from what you already own, including Mind Eraser.