Step 1

Line an 8x8-inch baking pan with a sheet of parchment paper large enough to fit up and over the edges (to help remove the fudge from the pan). Set aside.

Step 2

Place a medium saucepan over medium-low heat. Add the sweetened condensed milk, butter, vanilla, and salt; stir to combine. Cook, stirring continuously, until the butter melts and the mixture is hot but not yet simmering or boiling. Remove the pan from the heat.

Step 3

Pour the dark chocolate chips into the saucepan. Wait for a couple minutes, then stir until the chips have completely melted and everything is well combined.

Step 4

Pour into the prepared pan, and use an offset spatula to smooth the top.

Step 5

Use the back of a spoon or a butter knife to scoop a little bit of the marshmallow fluff. Drag the marshmallow fluff along the top of the fudge very lightly to create spooky streaks.

Step 6

Sprinkle on the red sprinkles, then place the small and large candy eyeballs all over the top.

Step 7

Let cool at room temperature until firm, about 3 hours. Refrigerating will help it to cool faster, but may cause the fudge to become a bit dry and crumbly.

Step 8

When ready to serve, lift the fudge out of the pan and transfer to a cutting board to cut into small squares. Store in an airtight container at room temperature for up to 1 week.