The Unknown Mjolnir Armor was a variation of the Mjolnir Powered Assault Armor for Spartans in the canceled Halo MMO by Ensemble Studios. Several variations were designed, one of which had a chainsaw attached to the left arm. Unlike the other armor variants seen in the games, most of these designs are quite extreme and heavily stylized.
While developing the Halo games, Bungie, 343 Industries and Ensemble Studios have had to cut some content, such as vehicles, gameplay, and story elements, from the final products. Much of this content has been confirmed by videos and commentary in special edition DVDs, interviews with developers, and released concept art.