Goobster

Goobster is a creature from another dimension that accidentally got transported to Mobius during a lightning storm. He has a huge appetite for Chili Dogs and he will suck up and devour everything it can until it has eaten a sufficient amount of them. He is voiced by Ian James Corlett.

History
When Goobster was transported to Mobius, he saw Sonic run by, so he followed him. When Sonic and Tails discovered him, Tails decided to keep him as a pet. Goobster helped the heroes defeat Scratch and Grounder but then got hungry and started sucking up everything until Sonic gave him his retirement chili dogs.

Sonic decided Goobster was too dangerous to keep and they have to send him back to his own dimension. Before they could do this, Goobster was kidnapped by Scratch and Grounder and taken to Robotnik. The evil doctor tried to use Goobster's great power against Sonic and Tails, but they were able to free him and escape from Dr. Robotnik's Lair. Another lightning storm hit and the inter-dimensional portal re-opened and Goobster went through and returned to his parents.

Trivia

 * On the DVD, Robotnik Strikes Back, the back cover introduces Goobster as "Walter" for unknown reasons.