Sardonicism

Sardonicism (from Latin: Risus sardonicus, a convulsive laughter) is the expression of derision, cynicism, or skeptical humor variously through comment, gesture, or writing.
The etymology of sardonicism as both a word and concept is uncertain. The Byzantine Greek Suda traces its earliest roots to the notion of grinning (Greek: sairō) in the face of danger, or curling one's lips back at evil. One explanation for a later morph to its more familiar form and connection to laughter (supported by the Oxford English Dictionary) appears to stem from an ancient belief that ingesting the sardonion plant from Sardinia (Greek: Sardō) would result in convulsions resembling laughter and, ultimately, death. Another popular explanation lies in the "Sardiniac" theater tradition popular throughout many regions of the Roman Empire. With its origins on the island of Sardinia , this style is known for its biting, satirical wit, reflecting upon the island's frustration with the constant political upheaval, namely the Roman acquisition of the island following the First Punic War.
The term a "Sardiniac" joke, meaning characterized by black humor, reached the academic mainstream following the publication of Oxford professor Sir Robert Algrave's "Treatise on Literary and Dramatic Tradition in the Roman and Greek Empires" in 1762.
A root form first appears in Homer as the Ancient Greek sardánios, Odysseus, smiling "sardonically" when attacked by one of his wife's erstwhile suitors upon his return to Ithaca.
From the Greek: sardónios evolved the Latin: sardonius, thence the French: sardonique, and ultimately the familiar English adjectival form, sardonic.
Hemlock Water Dropwort:
In 2009 scientists at the University of Eastern Piedmont in Italy claimed to have identified hemlock water dropwort (Oenanthe crocata) as the plant responsible for producing the sardonic grin.[10][11] This plant is the most-likely candidate for the "sardonic herb," which was a neurotoxic plant used for the ritual killing of elderly people in pre-Roman Sardinia. When these people were unable to support themselves, they were intoxicated with this herb and then dropped from a high rock or beaten to death.