↑ Forgács Tamás: Magyar szólások és közmondások szótára (Dictionary of Hungarian Idioms and Proverbs), Tinta Könyvkiadó, Budapest, 2004, ISBN 963 9372 83 8
Etymology
ló(“horse”) +-vá(“into”) + tesz(“to make, to turn into”). The expression is connected to witchcraft. Long ago, popular superstition held that witches could not only ride broomsticks or fireplace pokers, but they could also turn their victims into horses and fly on them to their orgies. People thought that those who were turned into horses, were also tortured. Later, the meaning of "to torture" was replaced by "to trifle with", "to toy with", finally into the current "to deceive".[1]