Supernatural - Dean & Sam
Since his return from Purgatory Dean had changed. Sam had too, of course – both of them had been through a lot and that changes people. But Dean’s change was worrying; he had taken too easily to the violence Purgatory had required of him. Even now he was humming like burning down a house was no big deal.
An entire family of twisted, tormented souls anchored by violence and anger to their home and Dean was humming while he destroyed them. “Are you...” the tune finally registered in Sam’s mind, “Dean, are you singing Walk Through the Fire?!”