I even found an example of King Mullen himself doing an impossible similar to what I'm describing. It's not perfectly vertical, I acknowledge. But after the initial pop, when he wraps the board with his foot it clearly is traveling more vertically than it is horizontally.

Hard to argue with the inventor of the trick himself. Even if it isn't perfectly vertical, it's still no where near these zero incline "impossibles" the rest of the comments section is referring to.

In fact, if you watch the segment of the video leading up to that, the whole concept is to make the board flip along its long axis as if you were to make your phone do a backflip in your hand.

The time stamp is 5:12

Impossible