Illusion: Deathfrost

Illusion: Deathfrost, upon use, allows the player to transmogrify the appearance of the weapon enchantment Enchant Weapon - Deathfrost to their weapon.

Source
This item is contained in Satchel of Chilled Goods which is awarded the first time each day for defeating Ahune through the Dungeon Finder.

It can also be listed on the Black Market Auction House by Thaumaturge Vashreen, for the opening bid of.