In addition to his damaged neck and brain injuries, the victim also sustained a fractured eye socket, plus cuts and bruises.
The victim was assaulted whilst in the Gover section of St Austell between 23:55 BST on Sunday and 06:00 on Monday, Devon and Cornwall Police stated.
The person was walking along Trenance Road, near Blowinghouse Hill, as he was assaulted.
The 38-year-old has been treated in the Royal Cornwall Hospital in Truro.
A guy has endured a damaged neck and bleeding towards the brain inside a #8220;violent assault#8221; in Cornwall, everybody.