Grebnedlog was the captain of the Pakled ship Mondor that was encountered by the USS Enterprise-D in 2365.
After Grebnedlog had asked for repair assistance, he captured Chief Engineer Geordi La Forge and held him hostage. The Pakled got their technology by stealing it from other species, so Grebnedlog informed Commander Riker that he would release La Forge if all the information from the Enterprise-D computer were transferred to his ship. After La Forge managed to disarm the Pakled's on-board weapons, Riker threatened to destroy them and faked the destruction of their weapons by means of a crimson force field. Grebnedlog, impressed by this force field, released La Forge because the Enterprise-D was "strong".
Grebnedlog later realized that he had been deceived, and swore vengeance against the Starfleet officers, Riker in particular. The Borg invasion of sector 001 in 2373 gave him such an opportunity, and Grebnedlog boarded the Borg cube and demanded to be assimilated. The Borg would not acquiesce to Grebnedlog's request however, deciding that the mental capacity of the Pakleds as a species made them unworthy of assimilation. As the Battle of Sector 001 progressed, however, the cube sustained severe casualties and decided to embark on an emergency assimilation program, meaning that Grebnedlog was now eligible for assimilation. The Borg placed Grebnedlog in an assimilation chamber and fulfilled his dreams by transforming him into a Borg drone. Unfortunately for Grebnedlog, he died ten seconds later when the Enterprise-E arrived on the scene and assisted in destroying the cube.