Lamia

The Lamia are a race of vaguely leonine centaurs which inhabit deserts. They are also fond of human flesh. The human half of the Lamia are exceptionally attractive. Well, possibly. Lamia are illusionists and charmers, capable of taking on human guise. Their touch also has a stupefying effect, making the effects of their spells all that more effective.

The illustration of the Lamia in the Monster Manual always kinda bothered me because everybody knows Lamia are snake-women duh Wizards. Well turns out the duh may be a bit on me. Doing a bit of research of the monster actually revelead a few things. For starters, there are numerous interpretations of what the Lamia looked like, among which is a woman who is a snake from the waist down. But it seems like the D&D Lamia was inspired by the Lamia from Topsell's The History of Four-Footed Beasts, a 17th century book, though that illustration may have been inspired by an even earlier one. Helps make it a bit different from Medusa and Naga.

The Greek myth of the Lamia is actually a somewhat interesting and confused one. The bare bones is Lamia is a Lybian princess who has the misfortune of catching Zeus' eye. She gives birth to babies, Hera kills her babies (and makes Lamia eat them), and Lamia is driven mad by grief and rage. She feels compelled to steal children and devour them. At some point she turns into a monster, the physical appearance of which is left vague. Also she can't close her eyes, but is able to remove them from her head. From that point on she tends to get mythologically confused with drakainae (female dragons), and empusa and lamaie (succubi and vampires). The Greek gods were jerks.

So the Lamia is one of many monsters seen worldwide throughout folklore: that of a woman who loses/kills/eats her children and goes to do the same to other children. La Llorona seems like the most modern version of that archetype, though I wouldn't be surprised if there were urban legends that followed a similar narrative pattern.