A "million dollar idea" for give

Yesterday there was news of a famous person killed by a shark while surfing. It reminded me of the Navy's unsuccessful, long-time search for shark repellent. It also reminded me of film (pre-video days, perhaps pre-transistor days) in which researchers demonstrated that, while sharks may be drawn to blood, they strike at an electrical field, at an electrode placed some distance from the researcher's bait. This "million dollar idea," which I hereby give away, is to put a 9v battery in the surfboard, which energizes a 'decoy' being towed behind the board. You could be cute and shape it like a fish ... for marketing purposes, the sharks won't care. I can imagine using surfboard itself as the decoy ... but I wouldn't want to be tethered to a surfboard undergoing a shark attack. Experimentation would have to determine best configuration. Given that 9v batteries can deliver five and six digits of voltage thru a stungun, the drogue decoy might be constructed to punish any shark that takes the bait. I'm making this stuff up as I go... Somebody save me.