It's hecatomb. hecatomb (ˈhɛkəˌtəʊm; -ˌtuːm)
n
(Historical Terms) (in ancient Greece or Rome) any great public sacrifice and feast, originally one in which 100 oxen were sacrificed
a great sacrifice
[C16: from Latin hecatombē, from Greek hekatombē, from hekaton hundred + bous ox]