The Glaistig, or Green Lady Phantom, is a shape-shifting spirit from Scottish folklore, appearing as a beautiful woman in green or a monstrous half-goat, half-woman creature (maigndean uaine), often linked to rivers, castles, and herding; she can be a protective spirit for cattle or a malevolent phantom luring travellers to their doom, embodying nature's dual, untamed power.

Key Characteristics
- Appearance: Upper body of a woman, lower half goat-like with cloven hooves; sometimes fully human but pale with golden hair, always in a green dress.
- Habitat: Found near water (rivers, lochs) in the Highlands, and haunting Scottish castles like Crathes.
- Nature: Duality is key—sometimes a benevolent guardian of cattle (offering milk), other times a dangerous trickster or murderer.
- Powers: Strong scream, control over cattle/deer, ability to transform.
Roles & Legends
- Protector: Guards herds, sometimes turning cattle to stone to save them (Arnadro).
- Vengeful Spirit: Lures men to their deaths or drowns them after being helped across water.
- Castle Haunter: A "Green Lady" in a castle (like Crathes) often stems from a tragic mortal woman, sometimes a jilted lover or murdered mother, appearing in a green dress, occasionally with a child.
Origins
- A spirit bound between worlds, an outcast fairy, or a human woman transformed by fae magic.
Notable Examples
- Crathes Castle: A famous Green Lady, possibly a jilted daughter, seen by the fireplace with a baby, with the bones of a child found beneath the hearthstone.
- Ackergill Tower: Helen Gun, a kidnapped woman, reportedly haunts this tower after leaping to her death.