Sonic the Werehog (ソニック・ザ・ウェアホッグ Sonikku za Weahoggu?) is a transformation that appears in Sonic Unleashed. A bestial, werewolf-like form of Sonic the Hedgehog, this transformation was created when Sonic accidentally absorbed a large dose of Dark Gaia's energy onboard the Chaos Energy Cannon, although the transformation itself would only be triggered by nighttime and remain active until daytime. Sonic eventually lost this form permanently when Dark Gaia reclaimed the energy that caused the transformation.
In Project X
Up from version 5.5 Werehog is one of bosses of Pumpkin Kingdom zone after Ghost Girl.
In this form, Sonic resembles a werewolf and gains more muscle mass and weight. He grows slightly larger, with a broader torso, a longer muzzle, larger hands, and longer, more muscular arms. Additionally, his finger nails become claw-like and his teeth become fangs. Likewise, his ears become more curved and thin, and his lips become black. His once peach skin is now a pale blue. His fur grows into a lush, heavy, dark blue coat. He also gains fur in places in places he normally does not, such as on his arms and chest. Traits of white fur also appear on his wrists, the end of his quills, and on his chest.
For attire, Sonic loses his white gloves, exposing his hands, and his socks becomes slightly frilled in the back. The white stripe on his shoes is replaced with grey metal that has three spikes on the surface. The bottom of each of his soles are now covered with eighteen small, metal spikes.