Sonic Unleashed is a 2008 platform game developed by Sonic Team and published by Sega. An installment in the Sonic the Hedgehog series, it follows Sonic as he attempts to restore the world after his nemesis Doctor Eggman shatters it with a powerful laser to unleash an ancient evil known as Dark Gaia, while struggling with his new "Werehog" form, a werewolf-like affliction. Gameplay features two distinct styles: daytime stages incorporate Sonic's traditional platforming and trademark speed; while night-time stages see Sonic transform into the Werehog and engage in slower combat against waves of enemies using the Werehog's brute strength.