Add the cranberry juice, ice, and 2 drops of black gel coloring. Shake well to combine and chill.
2 ounces cranberry juice, Black gel food coloring, 1 cup ice
Use a strainer to pour into your cocktail glass. Enjoy!
Notes
For a fun Halloween touch, try rimming your martini glass with orange or black sanding sugar and putting a gummy worm on the edge of the glass.
You could also add red food coloring to corn syrup, then dip the rim in it. When you turn the glass right side up, it'll look like blood dripping down the sides.