Poison

Poison is something that makes you sick, and then you keel over and die. In more simplistic times, bottles of poison were easily identifiable due to their black labels, emboldened with the ever-familiar skull and crossbones warning symbol. Giving someone poison is a very effective way to do away with your enemies. If one is smart, they will find just the right chemical combination and dosage to make the poison untraceable, which will certainly come in handy for those not wishing to get caught.