wæter-egesa, m.n: water-terror.
Image: A siren from The Medieval Bestiary: ‘The siren is a deadly creature, half human, half bird or fish. Early sources say the siren is human (always female) from the head to the navel, and bird from the waist down. Later sources say that the siren is fish from the waist down, like a mermaid. They usually have wings. In some cases sirens are described as having both bird’s feet and a fish tail […]. Sirens charm men with their beautiful singing. Sailors who are attracted to the singing fall asleep; the sirens then attack the men and tear their flesh.’ Definitely sounds like a kind of wæter-egesa!