Add your white chocolate chips to a small microwave-safe bowl and heat on high for about 40 seconds, stirring every 20 seconds so it doesn't scorch. Once it's smooth and fully melted, transfer it into a small zip-top bag. Snip off just the tip of one corner with scissors so you have a thin piping stream.
Pipe a small white chocolate dot onto each grape to form the white of the "eyeball." While it's still wet, press a mini dark chocolate chip into the center of each dot to act as the pupil. Let these sit undisturbed until the chocolate firms up completely.
Take your whole mandarin oranges and use the black edible marker to draw simple triangle eyes, a nose, and a jagged smile right onto the peel. Let the ink dry fully before moving the oranges so the lines don't smear.
Lay your banana halves cut-side down on a cutting board or directly onto your serving platter. Press two mini dark chocolate chips into each one, pointed side facing down, to form simple ghost eyes.
Arrange your apple slices across the platter first, then drizzle them with caramel topping and sprinkle the chopped peanuts on top. Finish by arranging your ghost bananas, eyeball grapes, and jack-o'-lantern oranges around the apples until the whole tray looks full and festive.