I especially like how he said "If either blood, or poison is right, you guys are manga readers!" Which means that either solution is too brilliant to brilliant and unexpected for him to have thought of on his own, but one of them isn't even right!
Now I'm on the edge of my seat waiting to find out if I'm a manga prophet or not!
(even though I doubt its poison now since, as people mentioned, if poison worked, why wouldn't you just stab him with it.)
(unless Shikamaru has figured out how Hidan's immortality works and has developed a counter agent and it has to be ingested....)