A grue is a grisly little comic poem with sadistic content and trick last lines. They are sometimes known as "Little Willies" because of the "hero" of many of them. The word was coined by no less a personage than Robert Louis Stevenson, from "gruesome".

Although their content is certainly no worse than the daily news, most grues are anonymous.

Willie poisoned father's tea
Father died in agony.
Mother looked extremely vexed;
"Really, Willie," she said, "what next?"