A freakin’ Yang Bo
Among the most difficult and most under-valued beam elements in existence, the Yang Bo remains an elusive endangered species on beam because…well…look at that picture of it in the code. That’s not even a human position.
Unlike its closely related—and equally valued—cousin the split ring jump, the Yang Bo requires oversplit (with both legs) along with head release, precluding all but the most flexible of Chinese gymnasts from even imagining attempting it.
Other skills often get misidentified as the Yang Bo, but remember the Yang Bo is not a ring element and does not require a ring position with the back leg.