A basilisk whose gaze turns you to ice. Hide behind ice pillars, and make it stare at one.
Enter with ::~skarn
The Mirrormere froze solid the winter the Rimeglass Basilisk crawled out of the deep. The fishers of Hollin's Ferry who looked at it turned to ice where they stood. The ferry-wardens learned that its own gaze, bounced off clear ice, blinds it.
Pray
"Frost!" (Skarn and Rime): Protect from Magic.
"Fang!" (Hoar, phase 2): Protect from Melee.
The hit lands 3 ticks after the shout.
Move
"... SEES YOU!": it stands still and charges its gaze (4 to 6 ticks). Put an ice pillar between you and the monster or take 60 to 85. A red mark under your feet means you are seen.
It walks round the room, so the pillar that covers you changes. Re-position every cycle.
Pillars crack as they absorb gazes (whole, cracked, ruined, gone).
Hit it
A gaze that finds nobody shatters on the pillar and Dazzles the monster. While Dazzled it takes 250% damage (otherwise 20%).
Phases
Split at 700 hitpoints: Skarn becomes Hoar (bone white, hunts you, melee Fang) and Rime (blue, circles the shore, Frost). The pillars come back. Dazzle both in turn.