Ovid Book 5

Phineus, the former fiancé of Andromeda, bursts into Perseus and Andromeda’s wedding banquet to contest the marriage. Phineus hurls his spear at Perseus but misses. Perseus retaliates, and a melee ensues. At one point, over a thousand men surround Perseus. He turns them to stone by pulling out Medusa’s head. Phineus pleads for his life, and Perseus promises that he will not touch him with his sword. He technically keeps his word but petrifies him with Medusa’s head.

Phineus is that jealous ex that comes back to be a home wrecker. In all seriousness though, Perseus needs to defend his marriage at all costs. His sly deception of Phineus is well thought out because if he were allowed to leave, he would return to do something once again.