Arabian double front
Carly Patterson (USA)
Or, according to the Code of Points, Karly Patterson. Because there’s enough time to name every skill after Nellie Kim but not enough time to check basic spelling.
One of only three beam dismounts rated at G or higher (the full-twisting double tuck and double-twisting double tuck being the others), the Patterson is performed by what remains quite an exclusive club—even a decade and a half after Carly Patterson unleashed it upon the world.
This is perhaps unsurprising since the number of gymnasts who even perform the double Arabian on the floor is somewhat meager, and the number of gymnasts able to perform it without terror-cowboy is even more meager. Taking it to the beam would be a drastic step.