Morell-Thule Lance Ornamentation gives your 2H Piercing weapon the look of Morell Thule's weapon that he wields in the House of Thule raid event Morell Ascendant.
This ornament can be purchased from Marketplace for 300 DB.
Or can be obtained from an Overseer Ornamentation Dispenser -> Weapons of the Gods Ornamentation -> Morell-Thule Lance Ornamentation.