Bees are small enemies that are spawned by the Queen Beeboss in the Underground Jungle, and will also appear when destroying a beehive and occasionally when mining hive blocks that make up giant underground Bee Hives. They are not to be confused with summoned bees from the Bee Gun or the Honey Comb. Bees are immune to the Poisoned and Venomdebuffs. In Expert mode, they will inflict the Poisoned debuff to players. Bees may also spawn from mini hives found in the jungle which will drop and spawn bees.
Unlike summoned Bees, these bees do not die/despawn when entering water.
The damage done by bees is greatly increased in hard mode if you are playing on an expert mode world. This can easily catch players unawares, as bees are normally easily dealt with at this stage of the game.
Tips
Since they can spawn from hive blocks, it is recommended that you enter the hive with caution, even though they have almost no defense (2 and 5) and very little health. A pickaxe will kill them, even those made of copper. Even with this, breaking too many hives at once can cause a player with low-tier armor to die if not careful.