Redtide Sword

The Redtide Sword is a craftable Pre-Hardmode broadsword. When swung, it fires a small glowing cyclone that grows in size, pierces once, deals half the broadsword's damage and travels a short distance before popping, emitting glowing water projectiles in a large radius. Despite the projectile growing in size, its hitbox does not change. The projectile can also go through walls if close enough to it.

Trivia

 * Red tide is the term given to the occurrence of algal blooms, which are normally harmful to marine wildlife.