Almost a
rope-made spring, this bend is very secure knot, easy to tie (*) and to inspect, symmetric in form ( when it is not loaded), which I had never seen before - or I do not remember seeing it before. I wonder if it could possibly be used to absorb a sudden strong pull, that would had been devastating to a more compact, more "rigid" knot. I believe it deserves the name " Springy bend", indeed.
( In order to prevent an early, easy "closing"/compactification of the knot when it will be loaded, we have to dress it pulling the standing ends AND the tails as hard as we can.)
( *) By properly retucking the fisherman s knot, for example - although there are many other ways.