I had to slow down the gif a ton. He basically just doesn't put his foot down when he crosses. I feel like the strong shadows really bump up the black magic look.
In essence the tutorial is right but the trick is in the transition but that takes practice.
It's but like street magic levitation, although that is easier. After my brother and I saw it explained by the Masked Magician, we both gave it a go and nailed it first time.