I have seen this throw before; it is called "spaz." It usually happens when a novice player is flustered at their first tournament, but even seasoned pros have been known to "throw spaz" from time to time.
During my competitive years, I would plan on facing a player throwing "spaz" at least once during a tournament. This was always extremely valuable, as it showed clearly my opponent's frame of mind. Also, given the chance against an inexperienced ref, one can pull a "John McEnroe" and complain bitterly about use of an illegal throw (e.g., "Did you see that? He just threw dynamite! Are you going to let that stand?") Usually a ref will warn the other player, meaning that if they throw spaz again, they will most likely recieve a penalty.
The best prophylaxis against spaz is to simply train in your throws, slowly at first and then more quickly; form first, speed second. After a while, the throws will become second nature and you can move on to strategy and eventually tactical use of stylized throws (palm up paper, subliminal scissors, "Coney Island" paper, etc.)
Advanced players can also intentionally use spaz for subterfuge, intel gathering, and counterintel, but this practice is beyond the scope of this elementary treatise.