This character exists primarily or exclusively within the IDW Publishing continuity. Information in this article may not be canonical to the storyline of the games or any other Sonic continuity.
Sonic the Werehog
Gray, dark blue, white
Sonic the Werehog is a transformation that appears in the comic series and its spin-offs published by Sonic the Hedgehog IDW Publishing. It is a transformation of Sonic the Hedgehog that he could achieve while struck with an unknown ailment.
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. His once peach skin is now a pale blue. His fur grows into a lush, heavy, dark blue coat. Traits of white fur also appear on his wrists.
For attire, Sonic loses his white gloves, exposing his hands, and his socks becomes slightly frilled. He also he retains his sneakers in some shape and form.
During the time the world was broken apart by
Dr. Eggman's Chaos Energy Cannon, Sonic came down with an illness that caused him to transform into Sonic the Werehog. However, he eventually rid himself of that condition. 
↑ 1.0 1.1 Head writer
Ian Flynn has revealed on Twitter that Sonic the Werehog's measurements are the same as those of his game counterpart.
Alf Layla wa-Layla | Baker | Burning Blaze | Chaos' forms ( Chaos 1, Chaos 2, Chaos 4, Chaos 6, Perfect Chaos) | Color Power | Dark Queen | Dark Shadow | Darkspine Sonic | Devil Doom | Excalibur | Excalibur Sonic | Finalhazard | Gaia Colossus | Giga Metal | Hero Shadow | Hyper Mode | Hyper Knuckles | Hyper Sonic | Master Core: ABIS | Mephiles' monstrous form | Nega-Mother Wisp | Neo Metal Sonic ( Metal Madness, Metal Overlord) | Perfect Dark Gaia | Phantom Heavies ( Phantom Gunner, Phantom King, Phantom Magician, Phantom Rider, Phantom Shinobi) | Roboticization | Sonic the Werehog | Super transformation ( Classic Super Knuckles, Classic Super Sonic, Classic Super Tails, Flicky's Super State, Mecha Sonic's Super State, Pir'Oth Ix's Super State, Super Knuckles, Super Mighty, Super Ray, Super Shadow, Super Silver, Super Sonic, Super Tails, Ultimate Gemerl) | Ultimate Emerl | Void's transformation
Sonic the Comic Perfect Chaos | Super Sonic ( Mirror Zone)
Adventures of Sonic the Hedgehog Roboticization | Super Robotnik | Supreme High Robotnik
Archie Comics Pre-SGW
Chaos' forms ( Chaos 6, Perfect Chaos) | Chaos Knuckles ( Dark Mobius, Light Mobius) | Chaos Shadow | Crystalline Magic ( Crystal Golem) | Enerjak ( Dark Enerjak) | Finalhazard | Metal Overlord | Perfect Tikhaos | Roboticization ( Blaze Woman, Charmy Man, Espio Man, Knuckles Man, Mecha Knuckles, Mecha Sally, Mecha Sonic, Mecha Tails, Rose Woman, Rouge Woman, Shadow Man, Silver Man, Tails Man, Vector Man) | Super transformation ( Hyper Knuckles, Hyper Tails, Master Mogul, Super A.D.A.M., Super Armor Mega Man, Super Scourge, Super Shadow, Super Silver, Super Sonic ( Dark Mobius, In Another Time, In Another Place), Turbo Tails, Ugly Naugus, Ultra Sonic ( Eco Sonic, Polar Sonic, Solar Sonic)) | Titan Metal Sonic | Titan Tails | Werehog
Burning Blaze | Chaos Shadow | Crystalmancy ( Crystal Omega, Crystal Sonic) | Devil Doom | Monster Form | Neo Metal Sonic ( Metal Overlord) | Overclocked Nicole | Perfect Chaos | Perfect Dark Gaia | Roboticization ( Blaze Woman, Charmy Man, Espio Man, Knuckles Man, M'egga Man, Rose Woman, Rouge Woman, Shadow Man, Silver Man, Sonic Man, Tails Man, Vector Man) | Sonic the Werehog | Super transformation ( Super Armor Mega Man, Super Shadow, Super Silver, Super Sonic)
Sonic X Chaos' forms ( Chaos 2, Chaos 4, Chaos 6, Chaosbot, Perfect Chaos) | Cosmo's transformation | Dark Sonic | Final Lizard | Final Mova | Serpenter | Super Shadow | Super Sonic
IDW Burning Blaze | Master Overlord | Neo Metal Sonic | Sonic the Werehog | Super Neo Metal Sonic | Super Sonic
Chaos Dingo | Regeneration | Roboticization ( SatAM, Sonic Underground)