He's just copied an old idea ............
It's called the 'Stren Coil' which is made with 6lb bs Stren 'Gold' fishing line wrapped around a nail or similar and hot water poured over it and then dipped in cold water and it leaves the line like a coiled spring
I first heard of it in the States a few years ago where they use it tied into a fly leader on some of the trout streams as an indicator -- it gives the fish some slack line without the fish feeling any resistance
In fact it's in the fly fishing section on here, Ron and I talked about it ....