Cocktails and spirits writer Camper English likes playing with ice. His latest experiment is a ticking ice bomb (re: an ice cube filled with food coloring that slowly turns your beverage black as it melts).
Camper's brief explanation is enough to get you started:
"The first step was to make perfectly clear ice. Then I heated the stubby end of a bar spoon in a pot of boiling water and kept plunging it into the ice until I made a tunnel.
Then I added several drops of food coloring. After I let that freeze for a few hours, I added a couple drops of water and let that freeze. I then added more water to top it up and seal the cube.
Then it was time to add the time bomb to a beverage..."
- Try playing around with different variables; experiment with different colors or as Camper suggests, "fill with bitters, or citrus oil, or absinthe to change the flavor of a drink mid-way through it."