User blog comment:Miskos3/Fairy Tail Chapter 326: Natsu vs. Rogue, Review/@comment-203.87.139.100-20130405155943/@comment-7418318-20130405161339

The only instances of mind controlling I remember are Ultear possesing Jellal, Lapointe invading the Cardinals mind, Shadow and if you want to count it, Mest/Doranbolt fiddling with the memories of the Fairy Tail members.

Except for Shadow, non is really an option for manipulating Lucy (Doranbolt doesn't seem to have the necessary ability, Lapoint returned to being hair and Ultear is busy with other things). On top of that both Ultears and Lapoints possesions were not instant, so unless their powered-up future selfs also came back through the Eclipse gate, my money's either on Shadow or a not yet introduced being.

I wonder if Lucy might not actually be controlled, but is just in some kind of Trance. Maybe through her Celestial Spirit Magic she can feel something of the bad consequences of opening the gate and is reacting instinctively. A little like when she cast Urano Metria the first time.