What time is it when the clock strikes 13? Time to get a new clock.

 
A man goes to the doctor.

He tells the doctor he's been hearing strange buzzing noises all week. The sounds come and go at all times of day, but they have been most intense at night. Sometimes there are multiple distinct buzzes at a time, at different frequencies. The patient says he has hardly slept for the past week because of the intermittent buzzing.

The doctor asks if he has experienced any neurological symptoms, such as headaches or hallucinations.

The man says no, although he has been extremely fatigued, even considering the loss of sleep, and has frequently felt lightheaded and had chest pains. Twice, he has had dizzy spells and almost fallen down stairs.

The man finally stammers that his mucus and earwax has begun to taste sweeter, and become more viscous. He inquires as to whether this might indicate diabetes.

The doctor gives the patient a grave look and asks where he lives.

The man tells him.

The doctor's face falls. He takes a deep breath and begins to inform the man that he lives within a few miles of a secret government research facility. Until a few months ago, the facility had been conducting a project attempting to genetically engineer super-intelligent bees, and train them into soldiers.

The project had backfired. The bees had learned well from the military, but they had no desire to fight in human wars. Instead, they had applied the medical knowledge taught to them so as to refine a technique for turning the human body into a living hive.

The patient listens in horror as the doctor explains to him how the bees have colonized his chest cavity. How even now they are growing fungi and tending microscopic arthropod livestock in the man's vital organs.

Trembling, the man asks how long he has.

"A couple weeks, maybe three", says the doctor. "Although the last few days will be sheer agony. The bees do a remarkable job of keeping their hosts alive, but eventually they take their tolls and move on."

The man returns home. Not knowing what to do, he lights a cigarette and smokes it on his apartment balcony while listening to the bees' faint chorus.

About halfway through the cigarette, his girlfriend calls. They had been on a break, but she says she's thought long and hard, and come to the conclusion that he's the man she wants to spend her life with. In tears, she asks if there's anything on this Earth that could stop them from growing old together.

After a long pause, the man sobs,

"Oh, bees till my beating heart!"