The Beast in the Ice (World Tier IV): Gather Distilled Fear while completing Tier 30 or higher Nightmare Dungeons. After you have enough, visit the Occultist and craft the Glacial Fissure Nightmare Sigil, activate it, then you can fight The Beast in the Ice. The Skull Torch and Fell Steed Mount Trophies can potentially drop from this boss, in addition to Unique items exclusive to it.