The Thunder Bat is an enemy creature that appears in Sonic Unleashed. As a spawn of Dark Gaia, this creature feeds on negative emotions and is capable of possessing people.
The Thunder Bat is a mutated variant of the Dark Bat, altered by the absorption of excess Dark Gaia energy. Its body has a paris-green colouration and a pair of white, pin-prick eyes. While the Dark Bat is relatively harmless, the Thunder Bat is more aggressive and has the power to back up that aggression. It possesses electrokinetic properties and can generate an electrical field around its body, shocking those that try to attack it head-on. This serves to prevent Sonic the Werehog from using the creature to swing across pitfalls as it can shock Sonic's hand and cause him to fall to his doom.
As well as generating electrical fields around itself, the Thunder Bat can also fire bolts of electricity from its tail. These blasts have a long range and can briefly stun victims.