Terraria (Wiki): Bee Keeper

The Bee Keeper is a melee weapon that pierces enemies without consuming ammunition or mana.

The Bee Keeper is a broadsword that summons 1-3 friendly bee projectiles for each enemy hit. Its projectiles deal 33.33% of the weapon's damage (10 (desktop, console, mobile) / 7 (3DS, old gen consoles)) with an additional 50% to deal one extra damage. 

Friendly bees will focus on their nearest target and sting an unlimited number of enemies before dissipating after 10s, the moment it touches water or lava, or after ricocheting off solid blocks three times. A Bee Keeper can autoswing. Its attack reaches four tiles in radius. At an optimal distance, the Bee Keeper can pierce two enemies. However, multiple bodies will be damaged should they all line up for the player. It is one of the key components in crafting the Zenith.

When normally used, the Bee Keeper will not emit light, and attacks do not go through walls.

Combat-wise, the Bee Keeper is effective against waves of enemies and bosses even in Hardmode, especially when using the bees, because of its ability to deal damage and apply the Confused Debuff simultaneously. Even though PvP disables the majority of weapon-inflicted debuffs, the Bee Keeper's debuff strangely affects other players. All Flask items will imbue their unique effects since the Bee Keeper is a melee weapon.

With the Hive Pack equipped, it increases the chance of one additional Bee spawning 33.33% and increases the likelihood that all Bee projectiles will turn into Giant Bee projectiles 50%, which always deal 1-3 more damage, has a knockback of 0.5, can pierce enemies or ricochet off solid blocks four times in total, fly noticeably faster, and last 11s.

Both types of bee projectiles instantly disappear when they come into contact with water or lava. The summoned bees' damage is also impacted by armor penetration effects (from both the Shark Tooth Necklace and the Sharpening Station), adding bonus damage to all their hits.

The ability of friendly bees to finish off enemies wounded by the sword and severely harm or kill any additional enemies nearby makes them very useful for crowd control.

When using the Bee Keeper on worm enemies, a lot of bees will be released if they move directly through the area where the sword swings. 

The Bee Keeper performs better than the Falcon Blade in every way, including the selling price, despite being rarer.

The Bee Keeper is best modified with Legendary for overall stats improvement.