Archerfish

The Archerfish is a Pre-Hardmode gun obtained from Shadow Chests in the Abyss. It shoots out a stream of water in a similar fashion to the Water Gun, albeit much faster and damage-dealing, and can pierce up to 2 enemies before dissipating upon hitting a third.

The best modifiers would be Godly or Ruthless. Because of the weapon's autofire function, not all shots will damage the enemy when using a speed boosting modifier such as Unreal.

Trivia

 * The Archerfish is a fish in real life, which shoots a stream of water out of its mouth to hit insects above the water.