Complex sentence: Heracles threatens Hades with a stone, Hades and Cerberus flee, and a goddess, perhaps Persephone or possibly Athena, standing in front of Hades' thrown, prevents the attack.
Split into simpler sentences: Heracles threatens Hades with a stone, while Hades and Cerberus flee. A goddess, perhaps Persephone or possibly Athena, standing in front of Hades' thrown, prevents the attack.