Don't want to be too technical but "Death Spiral" is a Paragliding / Paramotoring maneuver like what you see after 3:06 on this video;
The actual incident that you see in the kite surfing video called "Death Loop" and it mostly happens when your left or right line get tangled around the safety release or around your harness hook (The only solution is a kite knife).
It happen to me once and I've almost seen the death angel's but hole.