The story “Blue Light” by the Brothers Grimm is about a soldier who is dismissed by a king without any reward after years of service. Wandering through the forest, he encounters a witch who asks him to retrieve a blue lantern from the bottom of a well. After bringing it up, the soldier realizes that the witch intends to betray him, so he defeats her and keeps the lantern.
When he lights the lantern, a magical dwarf appears, ready to obey his commands. The soldier uses this power to take revenge on the king, gain wealth and power, and eventually marry the king’s daughter.