A drug for the dead. It reanimates dead and dying flesh, but gives the host a craving for all flesh not of it's own, as well as the drug. Highly profitable, because clients keep coming for more. The only way to go cold turkey is to finally die.
Other than immediately making you a godless sadist, distributing this drug is the closest you'll get to having a drug-induced, army of zombies.
All it took was a shot of necrophetamine for that dead guy to decide it was time to take a bite out of the coroner!