What is Sonic's most powerful form?

Shadow the Hedgehog is the ultamate life form, that should tell you right there that he's strong and with his chaos spear, chaos blast, and chaos control that shows true power. Chaos control can control time and space. It's like i say Sonic is the good guy, Tails is the partner, Eggman is the bad guy... and Shadow is just a pure badass loner!!