Poisons in detective novels are one of the great romances in fiction. Writers of the genre are always looking for new ways to administer the deadly stuff, which gives us this trope: a murder method wherein poison is unwittingly self-administered when the victim licks an object coated in the poison. Other seemingly innocent lickable objects, such as stamps or envelopes, are also popular. Most often a mystery trope, considering the murder angle. Modern examples of are probably inspired by the novel/film The Name of the Rose, although one early example is from the Arabian Nights.