1. Get a pair of red sweatpants or pajama bottoms.
2. Get a long sleeve red shirt.
2a. If you can, use a pair of red pajamas, preferably a onesie, but a two-piece can work. If it's got footies, bonus.
2b. No footie pajamas? Locate a pair of yellow rain boots (or just wear your sneakers).
3. Grab some paper, cut out a white circle; color a lightning bolt in yellow--or use yellow paper--cut that out and then glue it on the circle. Use staples, tape, glue, whatever you prefer to adhere the symbol to your chest.
4. The secret weapon: A red swim cap.
5. Cut a domino mask out of red paper and either tuck it in under the cap or cut holes on the sides and run a rubber band or string through to hold it on your face.
6. Take some yellow pipe cleaners you can make little wings out of and stick them behind your ears.
7. Take remaining yellow pipe cleaner and make a "belt" that you can stick by your method of choice to the waist.
NOTE: I did not make this costume for Halloween, I was just bored.
Be safe out there and have fun!