At the wedding of the king of the Laipths, Perithoose, centaurs were invited as an attempt to quell the wars between his people and theirs. It is said that the centaurs became drunk on the wine and attempted to violate his bride, Hippodamia.
This led to the slaughter of all the centaurs present.
You wonder if, like at other times, the truce the centaurs were invited under was false -- an attempt to murder the Lapiths enemies and justify it.
What was not known, however, is that one of the creators of the centaurs -- Poseidom (who also created the horses), sought his revenge. As such, he cursed one of the wedding gifts -- a small statue of a horse -- to transform human women into true hippodamia -- centaur mares.
In this picture, Batgirl and Supergirl hav found the cursed Statue of Hippodamia and inadvertantly triggered its curse.
Wonder Woman
Supergirl and Batgirl
Supergirl and Lois Lane
Batgirl and Hawkgirl
April O'Neil and Elisa Maza
Ranma Saotome