It's the all mighty Nazo! If you don't know who Nazo is: Nazo's first (and only) appearance was at the end of an early promo trailer for Sonic X. He appeared for only a few seconds before the trailer ended. A picture of him was released around the same time as the trailer, and was labeled, "Nazo.jpg". This character sparked many theories, one suggesting he was a design for a Sonic X exclusive Super Sonic. The other, more famous one is that he was the ultimate villain. This led to the creation of Nazo Unleashed, a flash animation which can be found on Newgrounds and YouTube. Recently. SEGA has confirmed Nazo was concept for Super Sonic, but was scrapped and used the normal Super Sonic.
Just watch and read.
