A father who let his teenage son hold a party at the family home was attacked as he tried to keep out a gang of up to 40 weapon-wielding gatecrashers.
Mr Hogan was struck on the back of the head
Christopher Hogan, 47, was beaten about the head with a bat as he challenged the teenagers outside his home in Ringley, Bolton.
They also smashed windows, lights and vehicles outside the house on Friday.
Police are investigating the "unprovoked" attack, which left Mr Hogan with a gash to his head.
Mr Hogan was in the house with his wife, Carol, as his son's party - held for 20 friends - began in the garage.
He said the couple were laughing about the loud music when they heard a window smash, looked outside and saw the mob.
"I was confronted by around 40 youngsters all brandishing weapons," he said. "It was like a scene from a horror film. I realised I was in serious trouble.
"Then one of them slugged me with a bat. Everything went white, then dark and in slow motion. I thought if I go down they will stamp on me and leave me a vegetable."
Mr Hogan managed to stagger inside, blood gushing from a four-inch wound on his head.
Mr Hogan's son held a party in the garage of the family home
Terrified teenagers inside screamed and ran for cover as the thugs smashed windows and lights with golf clubs and other weapons.
Mr Hogan was kept in hospital overnight and had to have six stitches in his head wound. He added: "It is a massive shock.
"I just can't understand the mentality. I've never had so much as a parking ticket in my life and I trust in the police and I hope they really go to town."
The house is a former hunting lodge and is set in 16 acres of remote grounds.
Det Con Rick Barrett, of Bolton CID, said: "This was an unprovoked attack in a family home where a young lad has had some friends round for a party.
"Mr Hogan was struck from behind by an object or weapon and has sustained a serious injury to his head.
"If he had gone down outside, rather than staggering back into the house, it could have been a lot worse."