Herring Staff

The Herring Staff is a Pre-Hardmode summon weapon that is found in the Shadow Chests in the Abyss. It summons a Herring which charges at enemies in order to attack them. Unlike most minions, the Herring only takes up half a minion slot, allowing the player to summon twice as many Herrings as one-slot minions.

Trivia

 * Despite being named "Herring Staff", the actual minion spawned by the staff doesn't quite look like a herring, since herrings have a distinctive reflecting silver-like color, while the minion's color is dark blue.