I made this Batman cake last month for my nephew. I could not find anything but a Batman candle to place on top the cake, so I used a hanging decoration as the main image. Be sure to place a thick piece of paper behind the image so the buttercream does not seep through and discolor the image.
Them I drew a yellow oval with buttercream icing and piped a black Batman logo with clear piping gel that I colored black. A few sprinkles, a blue border, some little Batman bouncy balls and the cake was complete!