Which makes me think of this one:
A woman gets a phone call. A sinister voice hisses “I am the Viper. I will come in one year.” She’s inclined to shrug it off, but she puts new locks on the doors. Eleven months later, she gets a phone call. The same voice sneers “I am the Viper. I will come in one month.” She gets an alarm system and a large dog. Three weeks later, and another phone call. “I am the VIPER. I will come in one week.” Now the woman is terrified. The local police step up their patrols. Finally, six days later: “I am The VIPER! I come tomorrow.” The day dawns. The SWAT team is concealed in the living room. The doorbell rings. Fearfully, the woman eases back the deadbolts and opens the door.
And a small man in a toolbelt says “I am the Viper. I’ve come to vipe your vindows.”