The improbable cat - Allan Ahlberg

The story begins when a seemingly harmless kitten limps into the Burrell family's garden. The kitten gets bigger and bigger and soon the family, apart from the narrator David, are in thrall to the creature. They slowly descend into squalor and slothas they are sucked into the service of the now enormous black cat that has taken over their lives. Eventually Davy breaks the spell and sends in a pack of dogs to see off the cat, who makes a dramatic exit through the lounge window and is flattened by a passing truck.