Nightmare flip

The nightmare flip (also known as a nightmare kickflip hyperflip or nightmare varial flip), is an aerial skateboarding trick where the skateboarder kicks his board in order to make it flip 720 degrees along the board's long axis, while turning in a 180 degree motion toward the toe edge of the board, essentially combining a Double Kickflip, and a pop shove it. It was most likely invented by Rodney Mullen, an early skateboarder; however, it is also possible that it is simply a variation on one of his tricks, created by someone else.1

References

Skateboarding tricks glossary

Some people also refer to the Nightmare flip as the Varial Double Flip, in which the board does a varial kickflip but instead the board flips twice.

References:

The common talk between skater friends