I believe that is both real and a hoax at the same. It's real because Nintendo has confirmed in the recent months that they would CONSIDER on making a Majora's Mask remake for the 3DS, but it is also a hoax because if Nintendo really wanted to spread the word out, it would have exploded across the internet by now. I would be pleased if they do announce the official statement of the current development of Majora's Mask 3D. It would be also be great if it is also developed by GREZZO. In the meantime, I will still be waiting for the official release of Luigi's Mansion 2: Dark Moon!