Makes me think of the Orichalcos stones in Yu-Gi-Oh!: The Abridged Series:
"I turned it into a cute necklace to remember you, my love."
"You know that thing takes people's souls and I found it on a dead guy, right?"
"Embracing the magic of the Orichalcos had revealed humanity's true nature and ravaged the person I loved. So I did what any reasonable person would do: I embraced the magic of the Orichalcos."
"Well, that checks out."
"So let me get this straight: you lived in a nice place, some rocks fell from the sky, the place wasn't so nice anymore, so now you're using those rocks to kill everybody?"