The Poseidon is a Hardmode spell tome that drops from the Giant Clam mini boss. It shoots a circular Poseidon typhoon sigil that homes in on enemies and lingers on top of them for a short duration, repeatedly dealing damage until it dissipates. Each Poseidon typhoon will pierce 3 to 8 times. Poseidon typhoons will also rebound off of blocks 9 times before disappearing.
Its best modifier is Mythical.
- Poseidon can additionally be obtained from Sunken Crates in Hardmode at a 7% drop chance after the Giant Clam has been defeated.
- Due to the slow-moving nature of the projectiles fired from the weapon, it is not recommended to use the Poseidon against fast moving bosses, such as The Twins. It is best utilized against large groups of enemies, multiple segmented enemies, or singular slow-moving targets.
- The name of the weapon is a reference to Poseidon, the Greek god of the Sea and other waters.
- The shape depicted on the item and its projectiles resembles a trident, Poseidon's signature weapon.