The next day the doctor was grinning as thought about all those packages being delivered. Then his doorbell rang, it was a young teen age boy wearing a postman's suit.
"It's too early for halloween," sneered the doctor.
A heavy leather shoe slipped in the open door before he could close it. The angry young boy shoved a crumpled and torn envelope through the open door. The doctor bent and picked it up, and sneezed. He turned it over and saw it was one of his envelopes. The address label had been torn off and the envelope crushed and torn like it had been caught in some machinery. Stamped in purple ink under his return address were the words, "DAMAGED IN MAILS, RETURN TO SENDER."
The doc struck his head and in his best Homer Simpson said, "DOH!"
He had put his return address on all those envelopes, and oh, oh! The teenage postman, the virus was loose and more virulent than he'd intended, and he might be infected now.
He turned allowing the door to swing open, and ran toward his lab. "Antidote, antidote! Why didn't I make an antidote before mailing all those viruses?"