Sardonicism

[1][2] A form of wit or humour, being sardonic often involves expressing an uncomfortable truth in a clever and not necessarily malicious way, often with a degree of skepticism.

[6] In Theory and History of Folklore, Vladimir Propp discusses alleged examples of ritual laughter accompanying death and killing, all involving groups.

[9] From the sardónios evolved the Latin: sardonius, thence the French: sardonique, and ultimately the familiar English adjectival form, sardonic.

Risus sardonicus causes a patient's eyebrows to rise, eyes to bulge, and mouth to retract dramatically, resulting in what has been described as an evil-looking grin.

[10] In 2009 scientists at the University of Eastern Piedmont claimed to have identified hemlock water dropwort as the plant responsible for producing the sardonic grin.