Frostgrinder was the Vanir equivalent of the Bifrost Bridge.
History[]
Frostgrinder was created by the Vanir in the ancient past as an imitation of the Bifrost Bridge.
As part of his quest to make himself look like the ultimate and greatest hero of Asgard, Loki sent his adoptive brother Thor to Vanaheim, where the Rock Trolls had been exiled, where Thor battled Ulik.
When his plans went wrong, Loki was forced to aid his brother in activating Frostgrinder in order to escape, realizing that Mangog was too powerful of an adversary. Upon their exit, Loki destroyed Frostgrinder to prevent the Trolls from following and retaliating against Thor.[1]