This was my grandma's favorite joke

A man lives alone in his apartment. He never married, doesn't stay in touch with his family, and generally keeps to himself.

One day while at home watching TV, his phone rings and he answers it. A deep, slow voice says to him "the viper is coming...", and then hangs up before the man has any chance to respond. He thinks it was pretty strange, but he figures it must just be some kids playing a bad prank or something.

Half an hour later, his phone rings again. He answers it, and the same voice as before says "the viper is getting closer...". Then the phone hangs up just as before. The man is now a little bit nervous. Clearly someone is trying to scare him.

He puts it out of his mind, but no less than 10 minutes later his phone rings again. He hesitates, then answers it, and hears the voice tell him "the viper is almost here!".

"Who are you?!" the man shouts into the phone, but it was too late. The line was already dead. The man is very upset now and considers calling the police, but decides against it. He calms himself down, but 5 minutes later, the phone rings once more.

"The viper has come!"

The man, now terrified, changes his mind and decides to call the police, but as he's dialing the number, he hears a knock at the door. He get's up, and slowly walks towards the door. His hands are sweaty and his heart is racing. When he reaches the door, he hesitates for a moment - then reaches for the doorknob and pulls the door open.

Standing there is a short man wearing lederhosen who exclaims "Hello! I am ze vindow viper! I've come to vipe your vindows!"