Poludnica

"Pscipolnitsa is a mythical character common to the various Slavic countries of Eastern Europe. She is referred to as Południca in Polish, Полудница (Poludnica) in Serbian, Polednice in Czech, Poludnica in Slovak, Полудница (Poludnitsa) in Bulgarian and Russian, and Полознича (Poloznicha) in Komi, the Pscipolnitsa is a noon demon in Slavic mythology. She can be referred to in English as "Lady Midday". She was usually pictured as a young woman dressed in white that roamed field bounds. She assailed folk working at noon causing heatstrokes and aches in the neck, sometimes she even caused madness.
She will stop people in the field to ask them difficult questions or engage them in conversation. If anyone fails to answer a question or tries to change the subject, she will cut off their head or strike them with illness. She may appear as an old hag, a beautiful woman, or a 12-year-old girl, and she was useful in scaring children away from valuable crops. She is only seen on the hottest part of the day and is a personification of a sun-stroke." (ENG wiki)