Ulik

 Ulik was a member of the race of Rock Trolls and lives within caverns in the extradimensional realm of Asgard.

Biography
As part of his quest to make himself look like the ultimate and greatest hero of Asgard, Loki sent his adoptive brother Thor to Nornheim, land of the Rock Trolls, where Ulik battled with Thor. Contrary to his plans, Loki was forced to aid his brother in activating the Troll equivelant of the Bifrost Bridge, Frostgrinder, in order to escape, realizing that Mangog was too powerful of an adversary.

It is unknown if Ulik was still inside Frostgrinder when Loki destroyed it.