Unholy Trident

The Unholy Trident is a Hardmode magic weapon that fires fast magic tridents and has a fast fire rate, but a high mana cost. The projectiles pierce up to 2 enemies, and dissipate upon impacting a third. It has a chance to be dropped by Red Devils in The Underworld after defeating any Mechanical Boss.

Remix and Zenith seeds
On the Remix and Zenith seeds it can be found on Obsidian Lock Boxes and Shadow Chests with a lot less damage and mana cost.

Trivia

 * It can be considered a Hardmode version of the Gem staves, due to both weapons firing a projectile that pierces a limited amount of enemies in a straight line.