Utgard-Loki is a fictional character in the Marvel Universe.
Utgard-Loki was first mentioned in Marvel continuity when Thor told a group of children of a tale wherein he was bested in a contest by Utgard-Loki.
Utgard-Loki next appeared when he learned of Odin's disappearance and planned to take this opportunity to conquer Asgard. He began by invading Nornheim, and captured its ruler, the sorceress Karnilla. Utgard-Loki used a magical dust to turn the other residents of Nornheim into stone, and forced Karnilla to work as a slave in his fortress. This action deprived Asgard of a potential ally, a first step in removing all of Asgard's allies and forcing the Asgardians to fight the Frost Giants on their own.
However, Karnilla's lover, Balder the Brave came to rescue her. He melted Utgard-Loki's ice fortress, and reduced Utgard-Loki and the other giants to tiny size. Balder then rescued Karnilla and took her back to Nornheim, leaving the tiny giants in defeat.