Glowing sword

Enchantment
This is a sword imbued with fire magic. It's incantations glow and it is surrounded in flame when it is unsheathed.

Appearance
In the episode "Web Weirdos", Ed the spider finds this sword and a cape while looking for a gift for Barb in the woods. It is seen near the carcass of what seems to be a humanoid knight. He then wraps the sword in the cape and brings it to his wife in order to save their relationship; when this fails he uses the flaming sword to free Finn, Jake , and the two flies from his web and drops the sword on the ground.