The Witch-Queen of the Brocken
Festival colossus · Walpurgis Night
On Walpurgis Night she comes down from the mountain on a storm, crooked crown on her head and a bone staff in her hand, to see whose fires burn brightest. She means to put them out.
Its mechanic: Shapeshifter
Every few hours she takes a new shape: a crow, a black cat, a toad or a serpent. Your companion familiar's type against her shape sets your damage: double if it is strong against her, half if it is weak, and three-quarters with no companion at all. Offer a Witch-sigil at her fire to force her into her next shape early.
Rare looks it drops
Everyone who strikes it has a chance at one piece whose look they haven't collected yet. Soulbound, and kept in the Wardrobe for good.