Stoor Worm

In Orcadian retellings (preserved by collectors such as Walter Traill Dennison and Ernest Marwick and later popularized in children’s anthologies), the Mester Stoor Worm is presented as a perennial calamity afflicting the kingdom of Leegarth. The tale frames the worm as a protracted, existential threat: it terrorizes the shores and countryside, prompting the king’s council to seek remedies and to offer tribute. The youngest son‑hero Assipattle, a resourceful youth of the household at Leegarth, undertakes a plan to confront the beast. His successful killing of the worm is narrated etiologically: the carcass and the effects of the combat are used to explain the formation of local islands and other large natural features (retellings state the story "describes how Orkney and Shetland were formed, and the smouldering volcanoes of Iceland!"). Sources situate the story within 19th–20th century collections and later popular retellings rather than as a single canonical medieval text.

Told as serpent‑like or dragonlike and an inhabitant of the sea, the creature is described in Dennison's long text and later retellings as of enormous, almost incalculable length ('beyond telling, and reached thousands and thousands of miles in the sea'). Some accounts characterize its head as 'like a great mountain.' Variants record its eyes differently: Dennison's variant says the eyes 'glowed and flamed like a ward fire,' a modern retelling describes them 'like round lochs, very deep and dark,' and some versions note it had only one eye. It is further said to possess a prehensile, forked tongue used like tongs to seize ships, houses or people, and to emit a putrid, poisonous breath that contaminates plants and kills animals and humans. In the Assipattle tale its teeth and body are narrated to form islands and lands after its death.

Attested powers and effects include a contaminating, poisonous breath that damages plants, animals, and people (sources describe it as capable of ‘‘contaminating plants and destroying animals and humans with its breath''). In narrative function it brings wide devastation to the kingdom of Leegarth, creating famine and turmoil that force the community to consider tribute and extraordinary measures. The worm’s presence is also linked in retellings to large‑scale landscape change; the combat with the hero and the disposition of the beast’s carcass are offered as etiological explanations for islands and volcanic phenomena in local lore. The creature thus operates both as a direct physical menace and as a mythic cause of major environmental transformations.