Peel each banana and decide whether you want to keep them whole or cut them into shorter ghost-sized pieces. Insert a popsicle stick into the cut end of each piece, then lay them on a parchment-lined baking sheet. Pop the tray into the freezer for about 15 minutes so the bananas firm up before dipping.
While the bananas chill, add your white chocolate chips and coconut oil to a microwave-safe bowl. Heat in 20-second bursts, stirring in between, until the mixture is fully smooth. Going slow here keeps the chocolate from seizing up or turning grainy.
Once your bananas are firm, take them out of the freezer one at a time. Hold each one by the stick and spoon the melted chocolate over the top, letting the excess drip back into the bowl. You want a nice even coat that covers most of the banana's surface.
While the chocolate coating is still wet, press two mini chocolate chips or candy eyes into the top half of each banana. This is the step my kids fight over the most, so I usually let them take turns adding the faces.
Return the finished ghosts to the parchment-lined tray and place them back in the freezer for about 10 minutes, or until the chocolate hardens completely. Once they're set, they're ready to serve right away or stored for later.