You need to launch the Origin application to see this deal. A promotional window will appear, scroll until you see the 'mystery deal' and click it.
The game (well, addon) I got was a DLC for Dead Space 3 (I game that I already own).
Not sure what you will get if you already own the DLC.
I own Dead Space 3, and also got the Awakened DLC offer…terms here:
https://www.origin.com/en-au/promo/mystery-offer---dead-spac…
It was a Dead Space 3 DLC for me as well: Awakened. The savings aren't bad $2.50 for a $10 DLC but I won't be playing Dead Space 3 anymore.
Same Awakened offer here too.
No offer for me either, I do only have the 'on the house' games however
Awakened DLC for me too.
It also suggested I add Dead Space 3 and Dragon Age Inquisition to my cart, which I already own on Origin.
No offer for me, by chance my damn GPU just crashed my system so I had to reload Origin - plus I just got this email :)
No such offer in my 'featured today' pop up. :(