Using Wilton Round Tip 2A and a small pastry bag, swirl a whipped cream ghost on top of each brownie.
Add candy eyeballs for the eyes.
That's it! They're ready to serve.
Video
Notes
I recommend not swirling the ghosts until you're ready to serve; OR refrigerate the ghost brownies until you're ready to serve them. Otherwise, your ghosts may start to melt.