Here is an idea of a super hero cake you can make. The bottom cake board has the spiderman web (which I made from black fondant) and spiderman (you can use a spiderman toy, spiderman candle or make one out of gumpaste). The Batman tier printed out a picture of the batman logo and used my cake knife to cut out a fondant version using the logo as a template. Then I made some simple buildings, and stars around the top. For the Superman Tier I covered it in Superman blue. I cut out a superman logo and cut out the yellow background of the logo. On yellow fondant I cut out a piece around the perimiter of the cake, then on red I cut around the perimiter then cut the background portions out. Carefully, carefully lift the red onto the yellow securing with a little water or sugar glue. I also cut out some silver stars and put them on wire and let them dry.
Another idea is you can just do one round tier and put the logos of batman, and superman on the sides and put a spiderman web on top with a spiderman face (you can make a face out of an egg cookie cutter and draw black lines on the red fondant and put on the eyes. Then put it on a tall pedistal and make superman, batman and spiderman cupcakes to go beneath.