Clash of the Titans

Perseus, is to marry Andromeda... but she's being sacrificed a sea monster, known as The Kraken, for sacrilegious reasons. The only way to defeat the said monster is to use the head of The Gorgon, Medusa... which of course, means killing HER, to kill The Kraken! Ray Harryhausen reprises the same animations he'd crafted in the not entirely dissimilar Greek mythological, classic film of 1963, "Jason and the Argonauts".