2x13 - He-Man and the Masters of the Universe

Using the power of the Medallion of Serpos, King Hssss transforms Snake Mountain into the mighty snake god, Serpos! Serpos begins to cause great destruction on Eternia, beginning with a vicious attack on the Royal Palace, then turning his attention on Castle Grayskull itself. He-Man and Zodak must combine forces to save the Masters and stop King Hssss from ruling all of Eternia!