I have heard it referred to as both. Is it really just what pops out when you are explaining it or is there a difference?
They are the same trick. Ninja Vanish is the “official” name. Back when the prelims at Worlds were compulsories (a set list of tricks, like Sport Ladder) instead of freestyles, they included this as one of the compulsory tricks but didn’t know what it was called. They used the name Flying Trapeze Green Triangle just to have something to call it, so some people learned it by that name.
Sort of the same as the barrel rolls name. Thanks for sharing the rest of the story though! As usually a very informed post thanks!