The Giant Bee, as its name suggests, is an oversized flying insect of the clade Anthophila. Closely related to wasps and ants, bees are known for their role in pollination and for many species producing honey and beeswax. Similarly to Giant Flies, it is unknown what made the bees brought by the Time Traveller so huge.
The Giant Bee will always appear as swarms and after a short pause, they will begin to attack any crew member it sees by piercing them with its large, venomous stinger, dealing damage and possibly inflicting Blood Sickness. They have very low health, but due to always appearing in large groups and being able to infect players with the Blood Sickness, they can be very dangerous to unprepared crews, particularly ones that do not have Items that can damage multiple enemies at once.
Due to their low individual health and their tendency to stay very close to each other, melee weapons such as the Sword can quickly dispatch the entire swarm due to being able to hit multiple enemies at once, but tend to be dangerous due to their ability to inflict Blood Sickness if the player is hit. Thus, it's generally advisable to use ranged weapons to eliminate the Giant Bees.
The Time Traveler's quote upon calling forth bees is a reference to the Animation called "Dr. Bees"