Coldfire Anvil (Patreon)

Wondrous item, rare

This cold, iron anvil weighs 50 pounds and is 1 and a half feet long. It has three magic runes on its side from the Everglacier that magically enchant any item sharpened, forged, or otherwise smithed using this anvil. Over the course of a full workday, or half as long if you're proficient with smith's tools, you can use the anvil to turn a nonmagical metal weapon into a coldfire one. A coldfire weapon is magical and deals an extra 1d6 cold damage to any target it hits, but is made fragile like ice. When you make an attack roll using a coldfire weapon and roll a 1, roll a d20. On a 9 or lower, the weapon shatters and destroys the weapon, releasing a biting burst of cold that deals 2d6 cold damage to all creatures within 10 feet of the weapon. After 7 days, a coldfire weapon loses the enchantment and becomes nonmagical again.

Once the anvil has been used to enchant a weapon in this way, it can't do so again for 1d6 + 1 days.

Born from metal and fire, but at home in the ice and cold. Some chills burn worse than fire.