Witch-killing bullets

Witch-killing bullets are a bullet version of Bobby Singer's witch-killing spell invented by Sam Winchester.

Appearances

 * Season 10
 * Brother's Keeper
 * Season 11
 * The Bad Seed
 * Love Hurts
 * Season 12
 * American Nightmare
 * Regarding Dean
 * Twigs & Twine & Tasha Banes