There is a less common category of lullabies to the dying, which survives in the "Death Croon" from the Western Isles of Scotland and in bunch of songs of the Adyghe of the Caucasus. According to the article in the Garland Encyclopedia of World Music, the Adyghean songs have many weird, surreal black jokes - the writer conjectures that they were originally songs to accompany euthanasia rituals.