In a medium saucepan, combine 2 cups of semi-sweet chocolate chips, 1 can of sweetened condensed milk, 2 tablespoons of butter, and 1 teaspoon of vanilla extract. Heat over low to medium-low heat, stirring continuously for about 5-7 minutes until the mixture is fully melted and smooth.

Remove from heat and divide the mixture into two bowls. Add green food coloring to one bowl and mix well.

Line an 8-inch square baking dish with parchment paper. Pour alternating spoonfuls of the green fudge and plain fudge into the dish, then swirl gently with a knife.

Sprinkle crushed chocolate cookies, candy eyeballs, and Halloween sprinkles over the top before fudge sets.

Place in the refrigerator to chill for about 2 hours until firm, then cut into squares or rectangles.