Board Thread:General Discussion/@comment-27020644-20170123175703/@comment-27020644-20170130223112

Another theory I had invloving Eternity and his staff, is that it might be hinting at how the Soul Stone may appear. Eternity's staff is near the representation of the Soul Stone.

So maybe the Soul Stone will appear on a staff in a future movie. If this is the Easter Egg, then maybe that is why Gunn has said that he may or may not reveal the Easter Egg after GotG v.2, because maybe he wont be allowed to reveal information about the Soul Stone.