User blog comment:Yatanogarasu/What Did Blackbeard Do to Get the Gura Gura no Mi?/@comment-3119203-20110110043629

Since the Yami Yami no Mi can absorb anything (fire, weapons, etc) I think it is the second option. Since BB has the ability to cancel other devil fruits, I believe this is a power to absorb part of the fruits power. Since the person is alive (ace/luffy) the power doesnt work as well, but if the person is weakened, then BB can absorb all of the fruits power and gain its own strength. It sounds really confusing, but I think it makes sense