Some obscure NES accessory?
DD83 'nives 'n 'nades Feedback 56 (100%) Apr 29, 2015 #4 https://www.cheapassgamer.com/topic/304390-help-cant-figure-out-this-cordcable-nes/#entry10321196
XXPrimusXX CAGiversary! Feedback 11 (100%) Apr 30, 2015 #5 Awesome. Thank you for shedding some light on that.