Upon entering Olympus , the Gods decide whether to kill Thalia , Percy and Bessie ( the ophiotaurus ) who may hold the decision to tear down Olympus according to the Great Prophecy . Upon entering Olympus , the gods try to decide whether or not to kill Thalia , Percy , and Bessie ( the Ophiotaurus ) , as they may hold the means to destroy Olympus , according to the Great Prophecy .