A 44-year-old was attacked by a group of men in Inverclyde on Saturday night.
Police Scotland said the assault happened on Fore Street in Port Glasgow at around 11.10pm.
The man was taken to Inverclyde Royal Hospital where he remains in a stable condition, the force added.
Officers are appealing for anyone with information to come forward.
Detective constable Laura Sokolov said: “It’s vital we find out exactly what happened to this man and I’m appealing to anyone who saw what happened or has any information to get in touch.
“If you were in the Fore Street area around 11pm last night and have dash cam footage, please review this and bring anything of significance to our attention.”
Anyone with information is asked to contact Police Scotland on 101 quoting reference 5089 of June 17.
Alternatively, Crimestoppers can be contacted anonymously on 0800 555 111.