A possible concise summary is:
This is a horror story about Laughing Jack, a demonic clown who was once the imaginary friend of a lonely and abused boy named Isaac. Jack was trapped in a box for 13 years while Isaac grew up to be a serial killer who turned his victims into furniture. When Isaac returned to his old home, he ignored Jack, who broke free from his box and killed Isaac in revenge. The story is an urban legend with no historical evidence, but it suggests that Jack might still be lurking in the dark.
Here are the key facts extracted from the text:
1. The text is about an urban legend of Laughing Jack, a demonic clown who was once a friend of a lonely boy named Isaac.
2. Isaac received Laughing Jack as a gift in a colorful wooden box on Christmas Eve in the late 1800s in London.
3. Laughing Jack could only be seen by Isaac and they played together until Isaac was sent to a boarding school for killing a cat.
4. Isaac returned as an adult and became a serial killer who made furniture out of human remains.
5. Laughing Jack escaped from his box and killed Isaac for abandoning him and ignoring him.
6. The text ends with a question about the veracity of the legend and a suggestion that Laughing Jack might still be lurking in the dark.