Everyone was brought to the attention of the superman punch from GSP, who threw the punch with his jab hand followed by a rear leg kick.
Here Clay shows us how to first set up, then throw the superman punch with your cross hand. It is very important to first set this up properly with multiple low kicks and getting the opponent conditioned to you throwing that kick. Another option off this set up is the question mark kick.
With this version the real fun happens after the superman punch is landed, as that cross is then used as a hand trap for the rear high kick to land.
The key here is to not bring your body back into its stance after your cross and immediately throw the head kick. If you come back into your stance after the cross and then throw the head kick, you have lost your opening.
Remember fighting is a game of timing and inches. If you react a second too soon or too late, you could have missed your opening.
For more in depth analysis check out The Ultimate Guide to Striking for MMA, Muay Thai and Kickboxing.