|This character exists primarily or exclusively within the Sonic Underground continuity.|
Information in this article may not be canonical to the storyline of the games or any other Sonic continuity.
Jeff is an anthropomorphic penguin about Sonia's height. Slightly chubby in appearance, he has black and white feathers, white bushy eyebrows, black eyes with light green sclera, a medium-long yellow beak and yellow web feet. His attire includes a red trapper hat, an amethyst scarf, a purple jacket, and apple green mittens.
A devout follower of Queen Sauna, Jeff, along with Moe and Marty, would encounter Sonia the Hedgehog underneath their native icecap. Believing Sonia was Queen Sauna, who was prophesized to one day return to their kingdom and bring about an era of warmth and happiness, Jeff and his crew brought Sonia to their village. When their home began melting however, Jeff realized Sonia was not Sauna. Regardless, he, Moe and Marty still joined up with her and helped the Sonic Underground foil Dr. Robotnik's plans to melt the polar icecaps and flood Mobius.