In Caesar's Women, Servilia, after the affair of the infamous letter, is telling at Brutus that Cato "is not all there. He never was, even as a baby. Mormolyce got at him."
Who was Mormolyce? The Greek Myth Index tells us,
MORMOLYCE Or Mormolyceion (Mormolukeion), the same phantom or bugbear as Mormo, and also used for the same purpose. (Philostr. Vit. Apollon. iv. 25; Menandr. Reliq. p. 145, ed. Meineke; Aristoph. Thesm. 417 Strab. i. p. 19; Stob. Eclog. p. 1010.)
According to the OCD, Mormo was the the queen of the frightful Laestrygones who lost her own children and so murders other children. The Laestrygones are known to us from the Odyssey.
Odysseus at the Laestrygonians
Courtesy Wikimedia Commons