Originally Posted by
viperwasp
The whole arm thing was probably a nervous twitch... You see Madara just asked obito... thats why you had to resurrect me in this way. But it seems like Obito was not planning on resurrecting Madara at all? Or he changed his plan etc.
So Obito was caught off guard with what to say? Lie, tell the truth... tell a part truth? Say nothing? It showed him looking a little worried then it showed his arm and a twitch. I think it applied that Madara noticed this and realized Tobi/Obito had an other plan. And so he commented that "Knowing you, you probably had an other plan etc"
So I think it was just a twitch... a nervous twitch. Even more so since me and my friend found a sound effect translation guide. And it listed all the possible meanings of that sound effect. Without seeing the raw copy of this chapter we don't know the exact kenju or symbol used etc. But out of the whole list not to many of the sound effects made sense. One of them was a tightening or twitching sound effect. So we looked over the scene and it's really the only one that made any sense? We could be wrong... but I think that's it.