The Amulet of Warmfyre is a piece of magical jewelry seen in the Season 29 episode The Serfsons It was used to keep Marge's mother, Jacqueline alive after see got bitten by her ex-boyfriend, who was an Icewalker.
The amulet is a necklace with red jewels on it. The front of the amulet has a big red-orange jewel that is warm to the touch. You can almost see fire in it.
The amulet grants the wearer completely immune to Icewalker bites, which can make you frozen solid. If you put the amulet on if you have bitten, it will go away forever until you take it off.
- The word "Warmfyre" really sounds like "Warm Fire"