Thousands of pensioners are terrified of their gas and elctricity bills following reports of unprovoked assaults.
The first case was reported last January when Mr Pulcifer Threadknockit, of Norwich, was seriously injured by his bill from Eastern Electricity.
At the time Mr Threadknockit told police that when he came home from a shopping trip, the bill was waiting for him behind the kitchen door.
"It just jumped out and bit me on the ankle," he said. "I had to go the doctor for tetanus and rabies shots. It was very painful."
More reports of sporadic attacks have followed in various parts of the country during the year.
Mrs Hyacinth Plotdigger was lucky to survive an attack by a North Sea Gas Corp bill at her home in Middlesbrough just last week.
"I was making a pot of tea and it just jumped out of the letter rack and started scratching my arms," she said. "I was lucky my friend Milly was there. She helped to pull it off."
Home safety expert Colin Gerbil warned people, especially the elderly and infirm, to be careful with their bills.
"When you open them, put them in a secure place where they can't struggle free. We have found that leaving them near a radio playing Radio Four keeps them quiet."