Well, since there are not going to be new chapters out for a week I've had the itch to read over old chapters and I've noticed something about Allen's eye in a number of the arcs.
The first time being durin the fight with Eliade when the eye regenerates and Mana comes back. The squiggly look of the eye is there as it evolves into the the eye that we are now accustomed to seeing.
The second time (finally found it chapter 65 pg 5) was when Allen's eye went all crazy like when it felt all those akuma near.
Third time was when Allen (chapter 116-117) started and then synchroed over 100%
And then the last time I can think of is when Allen was playing the 14th's song in the ark.
Now with all these examples does anyone else think there is something significant here with the scar going out of a linear shape and all squiggly like. I at first thought it just happened during the 14th's song because that's where I think it happened the strongest but its happened actually quite a few times in the past.