cockroach

Every night, Frank would go down to the liquor store, get a six pack,
bring it home, and drink it while he watched TV. One night, as he
finished his last beer, the doorbell rang. He stumbled to the door and
found a six-foot cockroach standing there. The bug grabbed him by the
collar and threw him across the room, then left.
The next night, after he finished his 4th beer, the doorbell rang. He
walked slowly to the door and found the same six-foot cockroach standing
there. The big bug punched him in the stomach, then left.
The next night, after he finished his 1st beer, the doorbell rang again.
The same six-foot cockroach was standing there. This time he was kneed
in the groin and hit behind the ear as he doubled over in pain. Then the
big bug left.
The fourth night Frank didn't drink at all. The doorbell rang. The
cockroach was standing there. The bug beat the snot out of Frank and
left him in a heap on the living room floor.
The following day, Frank went to see his doctor. He explained events of
the preceding four nights. "What can I do?" he pleaded. "Not much" the
doctor replied. "There's just a nasty bug going around."