Line an 8" square pan or baking dish with parchment paper leaving an overhang.
Add the chocolate chips, milk, and butter into a medium pot over low to medium heat.
Stir the mixture until melted then stir in the vanilla extract.
Divide the fudge into 4 small bowls. Color one bowl black, one, yellow, one pink, and one teal. Add a few drops and stir until you reach the desired color.
Drop alternate tablespoons of each color into the square pan until all of the mixtures have been used up.
Allow the fudge to harden overnight before cutting into 2-inch squares.