During the 2008 “Secret Invasion” storyline, Thor rescues and heals Beta Ray Bill, who after being temporarily given Mjolnir, aids Thor in defending Earth against an invading force of alien Skrulls. Due to Loki’s deception, Thor battles and kills his grandfather Bor, and is banished from Asgard. With Thor’s hammer Mjolnir damaged in that battle, Thor seeks out Doctor Strange, who is only able to repair the hammer by transferring the Odinforce from Thor to Mjolnir, binding the two in a symbiotic relationship. With the repaired hammer, Thor is able to draw out the imprisoned Sif, and return her to her own body, thereby restoring Loki to his male body in the process.
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