Preheat oven to 350 degrees F and line a 9x9 baking pan with parchment paper or foil.
Add butter and chopped chocolate to a double boiler (or in a heat-proof bowl set over a saucepan with water) and bring water in the bottom of boiler to a simmer. Stir gently until mixture is just melted and smooth.
Whisk in both sugars, eggs one at a time, and vanilla. Fold in cocoa powder, flour, and salt just until combined.
In a separate medium bowl, beat cream cheese swirl ingredients together until smooth (I like to use a hand mixer). Tint with gel coloring to a bright shade of orange.
Reserve about ½ cup of brownie batter and spread the rest in the bottom of the prepared pan. Dollop cream cheese mixture over it, add remaining brownie batter in between, and drag a knife through to gently swirl.
Bake 30-38 minutes, until the cream cheese is set and a toothpick inserted into brownies comes out mostly clean with moist crumbs.
Remove brownies from oven, add sprinkles, and gently press in candy eyeballs. Let pan cool on a wire rack for at least 15 minutes before removing brownies from pan and slicing into squares.