Seasonal Events

It's Reining Deer / Beast from the East / Red Beast from the East / Gold Beast from the East / Black Beast from the East / Get All the Things! / Love Me Tender / B.F.F. / Did It All for the Glory of Love / Love Makes the World Go Round / Royal Audience / Eggsceptional Hunting / Eggstraordinary Hunting / Eggsemplary Hunting / Eggstreme Hunting / Eggstravagant Hunting / Seven Short of a Dozen /　Cascadier Survivor / Stylish Cascadier / Dapper Cascadier / Classy Cascadier / Refined Cascadier / Clogging Along / Cascadier for Life / Once in a Lifetime / Chock-full of Elemental Goodness　* Updated on 24/09/2012.
I checked my list of achievement and was like "omg! I don't have it! Is it a new event coming soon?"
But then I saw your post, it is the quest achievement for the Dalamud Horn, which I have already. ^^