Mephisto appears as a hulking demonic hedgehog with a defined humanoid physique and a unique 6-way opening jaw which reveals rows of yellow teeth and a stinger-like tongue which has a bone-colored long needle which it uses to pierce hearts. He has Sonic's back spike except it now has teeth/spikes growing from them, a long whip-like tail, a long pale X wound, and an orange ring with ritual symbols surrounding him. Lastly his pupils are oval shaped with horizon-lined cross-shaped pupils.