The sea monster in Greek mythology famously defeated by the hero Perseus is Kraken or more accurately, the creature is frequently referred to as Cetus. This enormous beast was sent to terrorize the city of Joppa and demanded a human sacrifice. Perseus, using the winged sandals and the reflection of his shield, outsmarted and ultimately defeated Cetus, saving Andromeda in the process. This tale embodies themes of heroism, sacrifice, and the triumph of good over evil, establishing Perseus as a legendary figure in Greek mythology.