Not new at all.
This debuted in late 2007 IIRC.
It has real world applicability.
Get caught underwater by an aquatic animal including but not exclusive to various types of shark and cephalopod (octopus) and one would be very happy to have this sort of defensive tool.
YouTube - Woman Attacked by Whale
YouTube - Stock Footage Scuba Diver Attacked By Shark
YouTube - Giant Octopus Attacks Diver
Note: Divers have been known to be drowned to death by curious/attacking aquatic fauna. Seriously.