Cut peeled bananas in half crosswise and insert a skewer into each half. Freeze until firm, about 1 hour. Microwave chopped semisweet chocolate (about 1 ounce per skewer) in 20-second intervals, stirring, until melted. Dip the bananas in the chocolate; press 2 candy eyeballs (available at craft and party-supply stores) into each and let set, about 10 minutes. Microwave marshmallows (about 2 per skewer) until puffed, 10 to 15 seconds. Stir until smooth; let cool slightly. Using a spoon, scoop up some of the marshmallow (it will stretch into a thread) and wrap it around the bananas. Transfer to a parchment-lined plate and freeze until serving.