Grimer is a goblin-like creature who appears as a recurring villain in the UK-published Sonic the Comic. Throughout the comic's original run, he served the evil Dr. Robotnik as his chief scientist and most devoted lackey. He is responsible for designing many of Robotnik's Badniks, including the super-Badnik Metallix. His genius is unparalleled except by Robotnik, but Grimer has always chosen subserviance rather than a position of power. He has proven his loyalty to Robotnik time and time again, but when the doctor was driven insane by constant defeats at the hands of Sonic the Hedgehog, Grimer found his devotion waning. Grimer warned Sonic and the Freedom Fighters of Robotnik's instability and his plans to destroy the planet Mobius, but after the doctor's scheme was thwarted, he went scurrying back to his master and attempted to try and bring the fat former dictator out of a depression by unleashing the monster known as Chaos upon the world. Spurred into action, Robotnik managed to gather the Chaos Emeralds, the Chaos creature and Sonic and friends to his fortress in the Dark Dimension, so that they could all be together as the planet Mobius came to an end. Chaos was defeated and the heroes triumphed, and Grimer - having finally realized that Robotnik was beyond saving - quit his post and left the doctor.
In Sonic the Comic Online, Grimer has been working behind the scenes orchestrating Sonic's fall from grace in the eyes of the Mobian people. Using all he had learned about Sonic over the years, Grimer approached mass-media mogul Percival Kane and offered him everything he would need to launch a smear campaign against Sonic. Grimer also created the Neo Metallix - a liquid-metal robotic shapeshifter - to impersonate Sonic and frame him for a multitude of crimes. With Sonic's reputation damaged beyond repair, Grimer's revenge was complete. Since revealing his involvement in Sonic's downfall, Grimer has not made any other appearances.